Given an array of integers, find if the array contains any duplicates.

Your function should return true if any value appears at least twice in the array, and it should return false if every element is distinct.

Example 1:

Input: [1,2,3,1]Output: true

Example 2:

Input: [1,2,3,4]Output: false

Example 3:

Input: [1,1,1,3,3,4,3,2,4,2]Output: true

想法：先对数组排序，然后判断相邻两个元素是否相等。相等返回true，否则返回false

class Solution {public:    bool containsDuplicate(vector
     
      & nums) {        if(1 == nums.size())            return false;        sort(nums.begin(),nums.end());        for(int i = 1 ; i < nums.size() ; i++){            if(nums[i ] == nums.at(i-1)){                return true;            }        }        return false;    }};