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 ...

對於一個長度為n+1的數組，其中每一個值的取值范圍是[1,n]，可以證明的是必然存在一個重復數字（抽屜原理），假設僅存在一個重復數字，找到他。 舉例：輸入：[1,3,4,2,1]，輸出：1 自己做的時候，要么時間復雜度到o(n2)，要么需要額外的存儲空間利用hashset，下面來分析一下 ...

287. 尋找重復數 這題的難點就在於下面的說明了，我們先不管下面的那些說明的要求，用常規的解法來解答下上的題目。 排序思想解法 先把原來的數組進行排序，然后逐個遍歷，一旦發現后一個元素和當前的元素相等，那么就返回，這就是我們找到了重復數字。但是這種思想，就不滿足說明里面的，不能改變原 ...

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 ...

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 an array of integers, find if the array contains any duplicates. Your function should return true if any value appears at least twice ...

Write a SQL query to delete all duplicate email entries in a table named Person, keeping only unique emails based on its smallest Id. ...