Description

Submission

class Solution {
    int a[30005];
public:
    int findDuplicate(vector<int>& nums) {
        int n = nums.size();
        for(int i = 0; i < n; ++i) {
            a[nums[i]]++;
            if(a[nums[i]] > 1) return nums[i];
        }
        return 1;
    }
};