Classic leetcode-style problems
Classic leetcode-style problems
nums and an integer target, return indices of the two numbers such that they add up to target.
You may assume that each input would have exactly one solution, and you may not use the same element twice.
You can return the answer in any order.
Example 1:
Input: nums = [2,7,11,15], target = 9
Output: [0,1]
Explanation: Because nums[0] + nums[1] == 9, we return [0, 1].
Example 2:
Input: nums = [3,2,4], target = 6
Output: [1,2]
Example 3:
Input: nums = [3,3], target = 6
Output: [0,1]
Constraints:
2 <= nums.length <= 104-109 <= nums[i] <= 109-109 <= target <= 109prices where prices[i] is the price of a given stock on the ith day.
You want to maximize your profit by choosing a single day to buy one stock and choosing a different day in the future to sell that stock.
Return . If you cannot achieve any profit, return .
nums, return true if any value appears at least twice in the array, and return false if every element is distinct.
Example 1:
Input: nums = [1,2,3,1]
Output: true
nums, return an array answer such that answer[i] is equal to the product of all the elements of nums except nums[i].
The product of any prefix or suffix of is to fit in a integer.
nums, find the subarray with the largest sum, and return its sum.
Example 1:
Input: nums = [-2,1,-3,4,-1,2,1,-5,4]
Output: 6
Explanation: The subarray [4,-1,2,1] has the largest sum 6.
nums, find a subarray that has the largest product, and return the product.
The test cases are generated so that the answer will fit in a 32-bit integer.
Example 1:
Input: nums = [2,3,-2,4]
6
[2,3] has the largest product 6.
nums, return the length of the longest consecutive elements sequence.
You must write an algorithm that runs in O(n) time.
Example 1:
Input: nums = [100,4,200,1,3,2]
Output: 4
The longest consecutive elements sequence is . Therefore its length is 4.
root of a binary tree, determine if it is a valid binary search tree (BST).
A valid BST is defined as follows:
a and b, return the sum of the two integers without using the operators + and -.
Example 1:
Input: a = 1, b = 2
Output: 3
Example 2:
Input: a = 2, b = 3
Output: 5
Constraints:
-1000 <= a, b <= 100001 <= prices.length <= 1050 <= prices[i] <= 1041 <= nums.length <= 105-109 <= nums[i] <= 109numsO(n) time and without using the division operation.2 <= nums.length <= 105-30 <= nums[i] <= 30nums is guaranteed to fit in a 32-bit integer.O(1) extra space complexity? (The output array does not count as extra space for space complexity analysis.)1 <= nums.length <= 105-104 <= nums[i] <= 104O(n) solution, try coding another solution using the divide and conquer approach, which is more subtle.1 <= nums.length <= 2 * 104-10 <= nums[i] <= 10nums is guaranteed to fit in a 32-bit integer.[1, 2, 3, 4]0 <= nums.length <= 105-109 <= nums[i] <= 109n sorted in ascending order is rotated between 1 and n times. For example, the array nums = [0,1,2,4,5,6,7] might become:
[4,5,6,7,0,1,2] if it was rotated 4 times.[0,1,2,4,5,6,7] if it was rotated 7 times.[a[0], a[1], a[2], ..., a[n-1]] 1 time results in the array [a[n-1], a[0], a[1], a[2], ..., a[n-2]].
Given the sorted rotated array nums of unique elements, return the minimum element of this array.
You must write an algorithm that runs in O(log n) time.
Example 1:
Input: nums = [3,4,5,1,2]
Output: 1
Explanation: The original array was [1,2,3,4,5] rotated 3 times.
Example 2:
Input: nums = [4,5,6,7,0,1,2]
Output: 0
Explanation: The original array was [0,1,2,4,5,6,7] and it was rotated 4 times.
Example 3:
Input: nums = [11,13,15,17]
Output: 11
Explanation: The original array was [11,13,15,17] and it was rotated 4 times.
Constraints:
n == nums.length1 <= n <= 5000-5000 <= nums[i] <= 5000nums are unique.nums is sorted and rotated between 1 and n times.nums sorted in ascending order (with distinct values).
Prior to being passed to your function, nums is possibly rotated at an unknown pivot index k (1 <= k < nums.length) such that the resulting array is (). For example, might be rotated at pivot index and become .
[1, 104]-231 <= Node.val <= 231 - 1root of a binary search tree, and an integer , return
p and q as the lowest node in that has both and as descendants (where we allow )."
root of a binary tree, return its maximum depth.
A binary tree's maximum depth is the number of nodes along the longest path from the root node down to the farthest leaf node.
Example 1:
Input: root = [3,9,20,null,null,15,7]
Output: 3
Example 2:
Input: root = [1,null,2]
Output: 2
Constraints:
[0, 104].-100 <= Node.val <= 100p and q, write a function to check if they are the same or not.
Two binary trees are considered the same if they are structurally identical, and the nodes have the same value.
Example 1:
Input: p = [1,2,3], q = [1,2,3]
Output: true
root of a binary tree, invert the tree, and return its root.
Example 1:
Input: root = [4,2,7,1,3,6,9]
Output: [4,7,2,9,6,3,1]
Example 2:
Input: root = [2,1,3]
[2,3,1]
root of a binary tree, return the level order traversal of its nodes' values.
(i.e., from left to right, level by level).
Example 1:
Input: root = [3,9,20,null,null,15,7]
Output: [[3],[9,20],[15,7]]
Example 2:
Input: root = [1]
Output: [[1]]
root and subRoot, return true if there is a subtree of root with the same structure and node values of subRoot and false otherwise.
A subtree of a binary tree tree is a tree that consists of a node in and all of this node's descendants. The tree could also be considered as a subtree of itself.
preorder and inorder where preorder is the preorder traversal of a binary tree and inorder is the inorder traversal of the same tree, construct and return the binary tree.
Example 1:
n, return an array ans of length n + 1 such that for each i (0 <= i <= n), ans[i] is the number of 1's in the binary representation of i.
Example 1:
Input: n = 2
Output: [0,1,1]
Explanation:
0 --> 0
1 --> 1
2 --> 10
Example 2:
Input: n = 5
Output: [0,1,1,2,1,2]
Explanation:
0 --> 0
1 --> 1
2 --> 10
3 --> 11
4 --> 100
5 --> 101
nums containing n distinct numbers in the range [0, n], return the only number in the range that is missing from the array.
Example 1:
Input: nums = [3,0,1]
Output: 2
Explanation: n = 3 since there are 3 numbers, so all numbers are in the range [0,3]. 2 is the missing number in the range since it does not appear in nums.
-3 and the output represents the signed integer -1073741825.n steps to reach the top.
Each time you can either climb 1 or 2 steps. In how many distinct ways can you climb to the top?
Example 1:
Input: n = 2
Output: 2
Explanation: There are two ways to climb to the top.
1 <= n <= 45coins representing coins of different denominations and an integer amount representing a total amount of money.
Return the fewest number of coins that you need to make up that amount. If that amount of money cannot be made up by any combination of the coins, return -1.
You may assume that you have an infinite number of each kind of coin.
nums, return the length of the longest strictly increasing subsequence.
Example 1:
Input: nums = [10,9,2,5,3,7,101,18]
Output: 4
Explanation: The longest increasing subsequence is [2,3,7,101], therefore the length is 4.
text1 and text2, return the length of their longest common subsequence. If there is no common subsequence, return 0.
A subsequence of a string is a new string generated from the original string with some characters (can be none) deleted without changing the relative order of the remaining characters.
s and a dictionary of strings wordDict, return true if s can be segmented into a space-separated sequence of one or more dictionary words.
Note that the same word in the dictionary may be reused multiple times in the segmentation.
Example 1:
nums and a target integer target, return the number of possible combinations that add up to target.
The test cases are generated so that the answer can fit in a 32-bit integer.
Example 1:
nums representing the amount of money of each house, return .
nums representing the amount of money of each house, return the maximum amount of money you can rob tonight without alerting the police.
Example 1:
Input: nums = [2,3,2]
Output: 3
Explanation: You cannot rob house 1 (money = 2) and then rob house 3 (money = 2), because they are adjacent houses.
Example 2:
Input: nums = [1,2,3,1]
Output: 4
Explanation: Rob house 1 (money = 1) and then rob house 3 (money = 3).
Total amount you can rob = 1 + 3 = 4.
Example 3:
Input: nums = [1,2,3]
Output: 3
A-Z can be encoded into numbers using the following mapping:
'A' -> "1 "
'B' -> "2 "
...
'Z' -> "26 "
To decode an encoded message, all the digits must be grouped then mapped back into letters using the reverse of the mapping above (there may be multiple ways). For example, can be mapped into:
m x n grid. The robot is initially located at the top-left corner (i.e., grid[0][0]). The robot tries to move to the bottom-right corner (i.e., grid[m - 1][n - 1]). The robot can only move either down or right at any point in time.
Given the two integers and , return .
nums. You are initially positioned at the array's first index, and each element in the array represents your maximum jump length at that position.
Return true if you can reach the last index, or false otherwise.
Example 1:
int) and a list (List[Node]) of its neighbors.
class Node {
public int val;
public List neighbors;
}
Test case format:
For simplicity, each node's value is the same as the node's index (1-indexed). For example, the first node with val == 1, the second node with val == 2, and so on. The graph is represented in the test case using an adjacency list.
An adjacency list is a collection of unordered lists used to represent a finite graph. Each list describes the set of neighbors of a node in the graph.
The given node will always be the first node with val = 1. You must return the copy of the given node as a reference to the cloned graph.
Example 1:
Input: adjList = [[2,4],[1,3],[2,4],[1,3]]
Output: [[2,4],[1,3],[2,4],[1,3]]
Explanation: There are 4 nodes in the graph.
1st node (val = 1)'s neighbors are 2nd node (val = 2) and 4th node (val = 4).
2nd node (val = 2)'s neighbors are 1st node (val = 1) and 3rd node (val = 3).
3rd node (val = 3)'s neighbors are 2nd node (val = 2) and 4th node (val = 4).
4th node (val = 4)'s neighbors are 1st node (val = 1) and 3rd node (val = 3).
Example 2:
Input: adjList = [[]]
Output: [[]]
Explanation: Note that the input contains one empty list. The graph consists of only one node with val = 1 and it does not have any neighbors.
Example 3:
Input: adjList = []
Output: []
Explanation: This an empty graph, it does not have any nodes.
Constraints:
[0, 100].1 <= Node.val <= 100Node.val is unique for each node.numCourses courses you have to take, labeled from 0 to numCourses - 1. You are given an array prerequisites where prerequisites[i] = [ai, bi] indicates that you must take course bi first if you want to take course ai.
m x n rectangular island that borders both the Pacific Ocean and Atlantic Ocean. The Pacific Ocean touches the island's left and top edges, and the Atlantic Ocean touches the island's right and bottom edges.
The island is partitioned into a grid of square cells. You are given an integer matrix where represents the of the cell at coordinate .
m x n 2D binary grid grid which represents a map of '1's (land) and '0's (water),
return the number of islands.
An island is surrounded by water and is formed by connecting adjacent lands horizontally or vertically.
You may assume all four edges of the grid are all surrounded by water.
words from the alien language's dictionary, where the strings in words are sorted lexicographically by the rules of this new language.
Return a string of the unique letters in the new alien language sorted in by the new language's rules. If there is no solution, return If there are multiple solutions, return .
n nodes labeled from 0 to n - 1. You are given an integer n and a list of edges where edges[i] = [ai, bi] indicates that there is an undirected edge between nodes ai and bi in the graph.
Return true .
n nodes. You are given an integer n and an array edges where edges[i] = [ai, bi] indicates that there is an edge between ai and bi in the graph.
Return the number of connected components in the graph.
nums and an integer k, return the k most frequent elements. You may return the answer in any order.
Example 1:
Input: nums = [1,1,1,2,2,3], k = 2
Output: [1,2]
Example 2:
Input: nums = [1], k = 1
Output: [1]
Constraints:
1 <= nums.length <= 105-104 <= nums[i] <= 104k is in the range [1, the number of unique elements in the array].O(n log n), where n is the array's size.arr = [2,3,4], the median is 3.arr = [2,3], the median is .intervals where intervals[i] = [starti, endi] represent the start and the end of the ith interval and intervals is sorted in ascending order by starti. You are also given an interval newInterval = [start, end] that represents the start and end of another interval.
Insert newInterval into intervals such that intervals is still sorted in ascending order by starti and intervals still does not have any overlapping intervals (merge overlapping intervals if necessary).
Return intervals after the insertion.
Example 1:
Input: intervals = [[1,3],[6,9]], newInterval = [2,5]
Output: [[1,5],[6,9]]
Example 2:
Input: intervals = [[1,2],[3,5],[6,7],[8,10],[12,16]], newInterval = [4,8]
Output: [[1,2],[3,10],[12,16]]
Explanation: Because the new interval [4,8] overlaps with [3,5],[6,7],[8,10].
Constraints:
0 <= intervals.length <= 104intervals[i].length == 20 <= starti <= endi <= 105intervals is sorted by starti in ascending order.newInterval.length == 20 <= start <= end <= 105intervals where intervals[i] = [starti, endi], merge all overlapping intervals, and return an array of the non-overlapping intervals that cover all the intervals in the input.
Example 1:
Input: intervals = [[1,3],[2,6],[8,10],[15,18]]
[[1,6],[8,10],[15,18]]
Since intervals [1,3] and [2,6] overlap, merge them into [1,6].
intervals where intervals[i] = [starti, endi], return the minimum number of intervals you need to remove to make the rest of the intervals non-overlapping.
Example 1:
Input: intervals = [[1,2],[2,3],[3,4],[1,3]]
1
[1,3] can be removed and the rest of the intervals are non-overlapping.
intervals where intervals[i] = [starti, endi], determine if a person could attend all meetings.
Example 1:
Input: intervals = [[0,30],[5,10],[15,20]]
Output: false
Example 2:
intervals where intervals[i] = [starti, endi], return the minimum number of conference rooms required.
Example 1:
Input: intervals = [[0,30],[5,10],[15,20]]
Output: 2
head of a singly linked list, reverse the list, and return the reversed list.
Example 1:
Input: head = [1,2,3,4,5]
Output: [5,4,3,2,1]
Example 2:
Input: head = [1,2]
Output: [2,1]
Example 3:
Input: head = []
Output: []
Constraints:
[0, 5000].-5000 <= Node.val <= 5000head, the head of a linked list, determine if the linked list has a cycle in it.
There is a cycle in a linked list if there is some node in the list that can be reached again by continuously following the next pointer. Internally, pos is used to denote the index of the node that tail's next pointer is connected to. .
list1 and list2.
Merge the two lists in a one sorted list. The list should be made by splicing together the nodes of the first two lists.
Return the head of the merged linked list.
Example 1:
k linked-lists lists, each linked-list is sorted in ascending order.
Merge all the linked-lists into one sorted linked-list and return it.
Example 1:
Input: lists = [[1,4,5],[1,3,4],[2,6]]
Output: [1,1,2,3,4,4,5,6]
The linked-lists are:
[
1->4->5,
1->3->4,
2->6
]
merging them into one sorted list:
1->1->2->3->4->4->5->6
head of a linked list, remove the nth node from the end of the list and return its head.
Example 1:
Input: head = [1,2,3,4,5], n = 2
Output: [1,2,3,5]
Example 2:
m x n integer matrix matrix, if an element is 0, set its entire row and column to 0's.
You must do it in place.
Example 1:
Input: matrix = [[1,1,1],[1,0,1],[1,1,1]]
Output: [[1,0,1],[0,0,0],[1,0,1]]
Example 2:
Input: matrix = [[0,1,2,0],[3,4,5,2],[1,3,1,5]]
Output: [[0,0,0,0],[0,4,5,0],[0,3,1,0]]
Constraints:
m == matrix.lengthn == matrix[0].length1 <= m, n <= 200-231 <= matrix[i][j] <= 231 - 1O(mn) space is probably a bad idea.O(m + n) space, but still not the best solution.m x n matrix, return all elements of the matrix in spiral order.
Example 1:
Input: matrix = [[1,2,3],[4,5,6],[7,8,9]]
Output: [1,2,3,6,9,8,7,4,5]
Example 2:
n x n 2D matrix matrix representing an image. Rotate the image by 90 degrees (clockwise).
You must rotate the image in-place, which means you have to modify the input 2D matrix directly. Do not allocate another 2D matrix for the rotation.
m x n grid of characters board and a string word, return true if word exists in the grid.
The word can be constructed from letters of sequentially adjacent cells, where adjacent cells are horizontally or vertically neighboring.
The same letter cell may not be used more than once.
s, find the length of the longest substring without repeating characters.
Example 1:
Input: s = "abcabcbb "
Output: 3
Explanation: The answer is "abc ", with the length of 3.
Example 2:
Input: s = "bbbbb "
Output: 1
Explanation: The answer is "b ", with the length of 1.
Example 3:
Input: s = "pwwkew "
Output: 3
Explanation: The answer is "wke ", with the length of 3.
Notice that the answer must be a substring, "pwke " is a subsequence and not a substring.
Constraints:
0 <= s.length <= 5 * 104s consists of English letters, digits, symbols and spaces.s and an integer k, you are allowed to choose any character of the string and change it to any other uppercase English character. You can perform this operation at most k times.
Return the length of the longest substring containing the same letter you can get after performing the above operations.
s and t of lengths m and n respectively, return the minimum window substring of s such that every character in t . If there is no such substring, return .
s and t, return true if t is an anagram of s, and false otherwise.
An Anagram is a word or phrase formed by rearranging the letters of a different word or phrase, typically using all the original letters exactly once.
Example 1:
Input: s = "anagram", t = "nagaram"
Output: true
Example 2:
Input: s = "rat", t = "car"
Output: false
Constraints:
1 <= s.length, t.length <= 5 * 104s and t consist of lowercase English letters.strs, group the anagrams together. You can return the answer in any order.
An Anagram is a word or phrase formed by rearranging the letters of a different word or phrase, typically using all the original letters exactly once.
Example 1:
Input: strs = ["eat","tea","tan","ate","nat","bat"]
Output: [["bat"],["nat","tan"],["ate","eat","tea"]]
s containing just the characters '(', ')', '{', '}', '[' and ']', determine if the input string is valid.
An input string is valid if:
s, return true if it is a palindrome, or .
s, return the longest palindromic substring in s.
Example 1:
Input: s = "babad "
Output: "bab "
Explanation: "aba " is also a valid answer.
s, return the number of palindromic substrings in it.
A string is a palindrome when it reads the same backward as forward.
A substring is a contiguous sequence of characters within the string.
strs2 in Machine 2 should be the same as strs in Machine 1.
Implement the encode and decode methods.
You are not allowed to solve the problem using any serialize methods (such as eval).
Example 1:
Input: dummy_input = [ "Hello ", "World "]
Output: [ "Hello ", "World "]
Explanation:
Machine 1:
Codec encoder = new Codec();
String msg = encoder.encode(strs);
Machine 1 ---msg---> Machine 2
Trie() Initializes the trie object.void insert(String word) Inserts the string word into the trie.boolean search(String word) Returns true if the string word is in the trie (i.e., was inserted before), and false otherwise.boolean startsWith(String prefix) Returns true if there is a previously inserted string word that has the prefix prefix, and false otherwise.1 <= word.length, prefix.length <= 2000word and prefix consist only of lowercase English letters.3 * 104 calls in total will be made to insert, search, and startsWith.WordDictionary class:
WordDictionary() Initializes the object.void addWord(word) Adds to the data structure, it can be matched later.m x n board of characters and a list of strings words, return all words on the board.
Each word must be constructed from letters of sequentially adjacent cells, where adjacent cells are horizontally or vertically neighboring. The same letter cell may not be used more than once in a word.
[nums[i], nums[j], nums[k]] such that i != j, i != k, and j != k, and nums[i] + nums[j] + nums[k] == 0.
Notice that the solution set must not contain duplicate triplets.
Example 1:
Input: nums = [-1,0,1,2,-1,-4]
Output: [[-1,-1,2],[-1,0,1]]
Explanation:
nums[0] + nums[1] + nums[2] = (-1) + 0 + 1 = 0.
nums[1] + nums[2] + nums[4] = 0 + 1 + (-1) = 0.
nums[0] + nums[3] + nums[4] = (-1) + 2 + (-1) = 0.
The distinct triplets are [-1,0,1] and [-1,-1,2].
Notice that the order of the output and the order of the triplets does not matter.
Example 2:
Input: nums = [0,1,1]
Output: []
Explanation: The only possible triplet does not sum up to 0.
Example 3:
Input: nums = [0,0,0]
Output: [[0,0,0]]
Explanation: The only possible triplet sums up to 0.
Constraints:
3 <= nums.length <= 3000-105 <= nums[i] <= 105height of length n. There are n vertical lines drawn such that the two endpoints of the ith line are (i, 0) and (i, height[i]).
Find two lines that together with the x-axis form a container, such that the container contains the most water.
[nums[k], nums[k+1], ..., nums[n-1], nums[0], nums[1], ..., nums[k-1]][0,1,2,4,5,6,7]3[4,5,6,7,0,1,2]nums after the possible rotation and an integer target, return the index of target if it is in nums, or -1 if it is not in nums.O(log n) runtime complexity.1 <= nums.length <= 5000-104 <= nums[i] <= 104nums are unique.nums is an ascending array that is possibly rotated.-104 <= target <= 104kkInput: root = [3,1,4,null,2], k = 1
Output: 1
Input: root = [5,3,6,2,4,null,null,1], k = 3
Output: 3
n.1 <= k <= n <= 10^40 <= Node.val <= 10^4Tpq[2, 105].-109 <= Node.val <= 109Node.val are unique.p != qp and q will exist in the BST.[0, 100].-104 <= Node.val <= 104[0, 100].-100 <= Node.val <= 100root of a binary tree, return the maximum path sum of any non-empty path.[1, 3 * 104].-1000 <= Node.val <= 1000[0, 2000].-1000 <= Node.val <= 1000[0, 104].-1000 <= Node.val <= 1000treetreeroot tree is in the range [1, 2000].subRoot tree is in the range [1, 1000].-10^4 <= root.val <= 10^4-10^4 <= subRoot.val <= 10^41 <= preorder.length <= 3000inorder.length == preorder.length-3000 <= preorder[i], inorder[i] <= 3000preorder and inorder consist of unique values.inorder also appears in preorder.preorder is guaranteed to be the preorder traversal of the tree.inorder is guaranteed to be the inorder traversal of the tree.-3.32.0 <= n <= 105O(n log n). Can you do it in linear time O(n) and possibly in a single pass?__builtin_popcount in C++)?n == nums.length1 <= n <= 1040 <= nums[i] <= nnums are unique.O(1) extra space complexity and O(n) runtime complexity?321 <= coins.length <= 121 <= coins[i] <= 231 - 10 <= amount <= 1041 <= nums.length <= 2500-104 <= nums[i] <= 104O(n log(n)) time complexity?"ace " is a subsequence of "abcde ".1 <= text1.length, text2.length <= 1000text1 and text2 consist of only lowercase English characters.1 <= s.length <= 3001 <= wordDict.length <= 10001 <= wordDict[i].length <= 20s and wordDict[i] consist of only lowercase English letters.wordDict are unique.1 <= nums.length <= 2001 <= nums[i] <= 1000nums are unique.1 <= target <= 10001 <= nums.length <= 1000 <= nums[i] <= 4001 <= nums.length <= 1000 <= nums[i] <= 1000"11106 ""AAJF " with the grouping (1 1 10 6)"KJF " with the grouping (11 10 6)(1 11 06) is invalid because "06 " cannot be mapped into 'F' since "6 " is different from "06 ".s containing only digits, return the number of ways to decode it.1 <= s.length <= 100s contains only digits and may contain leading zero(s).mn2 * 109.1 <= m, n <= 1001 <= nums.length <= 1040 <= nums[i] <= 105[0, 1], indicates that to take course 0 you have to first take course 1.true if you can finish all courses. Otherwise, return false.1 <= numCourses <= 20000 <= prerequisites.length <= 5000prerequisites[i].length == 20 <= ai, bi < numCoursesm x nheightsheights[r][c](r, c)result where result[i] = [ri, ci] denotes that rain water can flow from cell (ri, ci) to both the Pacific and Atlantic oceans.m == heights.lengthn == heights[r].length1 <= m, n <= 2000 <= heights[r][c] <= 105m == grid.lengthn == grid[i].length1 <= m, n <= 300grid[i][j] is '0' or '1'." " " ".1 <= words.length <= 1001 <= words[i].length <= 100words[i] consists of only lowercase English letters.false1 <= n <= 20000 <= edges.length <= 5000edges[i].length == 20 <= ai, bi < nai != bi1 <= n <= 20001 <= edges.length <= 5000edges[i].length == 20 <= ai <= bi < nai != bi(2 + 3) / 2 = 2.5MedianFinder() initializes the MedianFinder object.void addNum(int num) adds the integer num from the data stream to the data structure.double findMedian() returns the median of all elements so far. Answers within 10-5 of the actual answer will be accepted.-105 <= num <= 105findMedian.5 * 104 calls will be made to addNum and findMedian.[0, 100], how would you optimize your solution?99% of all integer numbers from the stream are in the range [0, 100], how would you optimize your solution?1 <= intervals.length <= 104intervals[i].length == 20 <= starti <= endi <= 1041 <= intervals.length <= 105intervals[i].length == 2-5 * 104 <= starti < endi <= 5 * 1040 <= intervals.length <= 104intervals[i].length == 20 <= starti < endi <= 1061 <= intervals.length <= 1040 <= starti < endi <= 106pos is not passed as a parametertrue if there is a cycle in the linked list. Otherwise, return false.[0, 104].-105 <= Node.val <= 105pos is -1 or a valid index in the linked-list.O(1) (i.e. constant) memory?[0, 50].-100 <= Node.val <= 100list1 and list2 are sorted in non-decreasing order.k == lists.length0 <= k <= 1040 <= lists[i].length <= 500-104 <= lists[i][j] <= 104lists[i] is sorted in ascending order.lists[i].length will not exceed 104.sz.1 <= sz <= 300 <= Node.val <= 1001 <= n <= sz[1, 5 * 104].1 <= Node.val <= 1000m == matrix.lengthn == matrix[i].length1 <= m, n <= 10-100 <= matrix[i][j] <= 100n == matrix.length == matrix[i].length1 <= n <= 20-1000 <= matrix[i][j] <= 1000m == board.lengthn == board[i].length1 <= m, n <= 61 <= word.length <= 15board and word consist of only uppercase and lowercase English letters.Input: s = "ABAB", k = 2
Output: 4
Explanation: Replace the two 'A's with two 'B's or vice versa.
Input: s = "AABABBA", k = 1
Output: 4
Explanation: Replace the one 'A' in the middle with 'B' to form "AABBBBA".
1 <= s.length <= 10⁵s consists of only uppercase English letters.0 <= k <= s.length" "m == s.lengthn == t.length1 <= m, n <= 105s and t consist of uppercase and lowercase English letters.O(m + n) time?1 <= strs.length <= 10^40 <= strs[i].length <= 100strs[i] consists of lowercase English letters.1 <= s.length <= 104s consists of parentheses only '()[]{}'.false1 <= s.length <= 2 * 105s consists only of printable ASCII characters.1 <= s.length <= 1000s consist of only digits and English letters.1 <= s.length <= 1000s consists of lowercase English letters.1 <= strs.length <= 2000 <= strs[i].length <= 200strs[i] contains any possible characters out of 256 valid ASCII characters.wordbool search(word) Returns true if there is any string in the data structure that matches word or false otherwise. word may contain dots '.' where a dot can represent any one letter.WordDictionary wordDictionary = new WordDictionary();
wordDictionary.addWord("bad");
wordDictionary.addWord("dad");
wordDictionary.addWord("mad");
wordDictionary.search("pad"); // false
wordDictionary.search("bad"); // true
wordDictionary.search(".ad"); // true
wordDictionary.search("b.."); // true
1 <= word.length <= 25word in addWord consists of lowercase English letters.word in search consists of lowercase English letters or '.'.2 dots '.' may appear in any search query.10⁴ calls in total will be made to addWord and search.m == board.lengthn == board[i].length1 <= m, n <= 12board[i][j] is a lowercase English letter.1 <= words.length <= 3 * 1041 <= words[i].length <= 10words[i] consists of lowercase English letters.words are unique.n == height.length2 <= n <= 1050 <= height[i] <= 104