题解 | #数组中重复的数字#

#include <unordered_map>
class Solution {
public:
    int duplicate(vector<int>& numbers) {
        unordered_map<int, int> mp;
        for(int i=0;i<numbers.size();i++)
        {
            if(mp.count(numbers[i]))
            {
                return numbers[i];
            }
            else {
                mp[numbers[i]]++;
            }
        }
        return -1;
    }
};