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. ...

287. 寻找重复数 这题的难点就在于下面的说明了，我们先不管下面的那些说明的要求，用常规的解法来解答下上的题目。 排序思想解法 先把原来的数组进行排序，然后逐个遍历，一旦发现后一个元素和当前的元素相等，那么就返回，这就是我们找到了重复数字。但是这种思想，就不满足说明里面的，不能改变原 ...

对于一个长度为n+1的数组，其中每一个值的取值范围是[1,n]，可以证明的是必然存在一个重复数字（抽屉原理），假设仅存在一个重复数字，找到他。 举例：输入：[1,3,4,2,1]，输出：1 自己做的时候，要么时间复杂度到o(n2)，要么需要额外的存储空间利用hashset，下面来分析一下 ...

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 ...

Given a list of directory info including directory path, and all the files with contents in this directory, you need to find out all the groups ...

letter at a random position. Find the letter that was a ...

Write a SQL query to find all duplicate emails in a table named Person. For example, your query should return the following for the above table ...

Given two strings representing two complex numbers. You need to return a string representing the ...