Ens

67. Add Binary Given two binary strings a and b, return their sum as a binary string. 1 2 3 4 5 6 7 8 9 Example 1: Input: a = "11", b = "1" Output: "100" Example 2: Input: a = "1010", b = "1011" Output: "10101" Constraints: ...

974. Subarray Sums Divisible by K Given an array nums of integers, return the number of (contiguous, non-empty) subarrays that have a sum divisible by k. 1 2 3 4 5 6 Example 1: Input: nums = [4,5,0,-2,-3,1], k = 5 Output: 7 Explanation: There are 7 subarrays with a sum divisible by k = 5: [4, 5, 0, -2, -3, 1], [5], [5, 0], [5, 0, -2, -3], [0], [0, -2, -3], [-2, -3] Note: ...

1897. Redistribute Characters to Make All Strings Equal You are given an array of strings words (0-indexed). In one operation, pick two distinct indices i and j, where words[i] is a non-empty string, and move any character from words[i] to any position in words[j]. Return true if you can make every string in words equal using any number of operations, and false otherwise. 1 2 3 4 5 6 7 8 9 10 11 12 13 Example 1: Input: words = ["abc","aabc","bc"] Output: true Explanation: Move the first 'a' in words[1] to the front of words[2], to make words[1] = "abc" and words[2] = "abc". All the strings are now equal to "abc", so return true. Example 2: Input: words = ["ab","a"] Output: false Explanation: It is impossible to make all the strings equal using the operation. Constraints: ...

1898. Maximum Number of Removable Characters You are given two strings s and p where p is a subsequence of s. You are also given a distinct 0-indexed integer array removable containing a subset of indices of s (s is also 0-indexed). You want to choose an integer k (0 <= k <= removable.length) such that, after removing k characters from s using the first k indices in removable, p is still a subsequence of s. More formally, you will mark the character at s[removable[i]] for each 0 <= i < k, then remove all marked characters and check if p is still a subsequence. ...

1899. Merge Triplets to Form Target Triplet A triplet is an array of three integers. You are given a 2D integer array triplets, where triplets[i] = [ai, bi, ci] describes the ith triplet. You are also given an integer array target = [x, y, z] that describes the triplet you want to obtain. To obtain target, you may apply the following operation on triplets any number of times (possibly zero): ...

31. Next Permutation Implement next permutation, which rearranges numbers into the lexicographically next greater permutation of numbers. If such an arrangement is not possible, it must rearrange it as the lowest possible order (i.e., sorted in ascending order). The replacement must be in place and use only constant extra memory. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 Example 1: Input: nums = [1,2,3] Output: [1,3,2] Example 2: Input: nums = [3,2,1] Output: [1,2,3] Example 3: Input: nums = [1,1,5] Output: [1,5,1] Example 4: Input: nums = [1] Output: [1] Constraints: ...

338. Counting Bits Given an integer 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. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 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 Constraints: ...

136. Single Number Given a non-empty array of integers nums, every element appears twice except for one. Find that single one. You must implement a solution with a linear runtime complexity and use only constant extra space. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 Example 1: Input: nums = [2,2,1] Output: 1 Example 2: Input: nums = [4,1,2,1,2] Output: 4 Example 3: Input: nums = [1] Output: 1 Constraints: ...

137. Single Number II Given an integer array nums where every element appears three times except for one, which appears exactly once. Find the single element and return it. You must implement a solution with a linear runtime complexity and use only constant extra space. 1 2 3 4 5 6 7 8 9 Example 1: Input: nums = [2,2,3,2] Output: 3 Example 2: Input: nums = [0,1,0,1,0,1,99] Output: 99 Constraints: ...

190. Reverse Bits Reverse bits of a given 32 bits unsigned integer. Note: Note that in some languages such as Java, there is no unsigned integer type. In this case, both input and output will be given as a signed integer type. They should not affect your implementation, as the integer’s internal binary representation is the same, whether it is signed or unsigned. In Java, the compiler represents the signed integers using 2’s complement notation. Therefore, in Example 2 above, the input represents the signed integer -3 and the output represents the signed integer -1073741825. Follow up: ...