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Given an array nums containing n + 1 integers where each integer is between 1 and n (inclusive), prove that at least one duplicate number must exist. 阅读全文
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Given a collection of distinct integers, return all possible permutations. Example: 阅读全文
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Given a non-empty array of integers, return the k most frequent elements. Example 1: Example 2: Input: nums = [1], k = 1 Output: [1] Example 2: Note: 阅读全文
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Given a binary tree, return the inorder traversal of its nodes' values. Example: Follow up: Recursive solution is trivial, could you do it iteratively 阅读全文
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Given a string, your task is to count how many palindromic substrings in this string. The substrings with different start indexes or end indexes are c 阅读全文
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Suppose you have a random list of people standing in a queue. Each person is described by a pair of integers (h, k), where h is the height of the pers 阅读全文
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Given a non negative integer number num. For every numbers i in the range 0 ≤ i ≤ num calculate the number of 1's in their binary representation and r 阅读全文