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题目：Given an array of integers, 1 ≤ a[i] ≤ n (n = size of array), some elements appear twice and others appear once.Find all the elements that appear twice in this array.Could you do it without extra s...

Given an array of integers where 1 ≤ a[i] ≤ n (n = size of array), some elements appear twice and others appear once.Find all the elements of [1, n] inclusive that do not appear in this array.Could yo...

Given an array of n integers where n > 1, nums, return an array output such that output[i] is equal to the product of all the elements of nums except nums[i].Solve it without division and in O(n).F...

Given a binary tree, return all duplicate subtrees. For each kind of duplicate subtrees, you only need to return the root node of any oneof them.Two trees are duplicate if they have the same structure...

题目描述：Given a string S and a string T, count the number of distinct subsequences of S which equals T.A subsequence of a string is a new string which is formed from the original string by deleting some ...

Given an array of integers and an integer k, you need to find the total number of continuous subarrays whose sum equals to k.Example 1:Input:nums = [1,1,1], k = 2 Output: 2 Note:The length of the arra...

Given an array consists of non-negative integers, your task is to count the number of triplets chosen from the array that can make triangles if we take them as side lengths of a triangle.Example 1:Inp...