[leetcode]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.
数组里有重复的返回1，都不重复返回0
知识点：set的使用，主要是为了使用count函数，降低开销，如果使用两个for遍历会timeout

#include <iostream>#include <vector>#include <set>using namespace std;class Solution {public:    bool containsDuplicate(vector<int>& nums) {        if(nums.empty()||nums.size()==1)    return false;        set<int> temp;        temp.insert(nums[0]);            for(int i=1;i<nums.size();i++)            {                if(temp.count(nums[i])==1)                    return true;                else                    temp.insert(nums[i]);            }            return false;    }};void main(){    int a[] = {3,2,4,2};    vector<int> nums(a,a+4);Solution *s = new Solution();// vector<int> result = s->twoSum(nums,6);// cout<<result[0]<<result[1];    bool result = s->containsDuplicate(nums);    cout<<result;}