Leetcode-217 Contains Duplicate

#217.    Contains Duplicate      

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.

题解：感觉自己第一想到的就是用set，没救了。

class Solution {
public:
    bool containsDuplicate(vector<int>& nums) {
        set<int> num;
        for(int i=0;i<nums.size();i++)
        {
            num.insert(nums[i]);
        }
        if(num.size()==nums.size())
            return false;
        else
            return true;
    }
};