题解 | #数组中重复的数字#

class Solution {
public:
    int duplicate(vector<int>& numbers) {
        if(numbers.size()==0)
        {
            return -1;
        }
        sort(numbers.begin(),numbers.end());
        if(numbers[0]<0)
        {
            return -1;
        }
        for(int i=1;i<numbers.size();i++)
        {
            if(numbers[i]==numbers[i-1])
            {
                return numbers[i];
            }
        }
        return -1;
    }
};