leetcode 217: Contains Duplicate

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