Today I have done leetcode's January LeetCoding Challenge with cpp.

January LeetCoding Challenge 2

Description

N-Repeated Element in Size 2N Array

You are given an integer array nums with the following properties:

• nums.length == 2 * n.
• nums contains n + 1 unique elements.
• Exactly one element of nums is repeated n times.

Return the element that is repeated n times.

Example 1:

Input: nums = [1,2,3,3]
Output: 3

Example 2:

Input: nums = [2,1,2,5,3,2]
Output: 2

Example 3:

Input: nums = [5,1,5,2,5,3,5,4]
Output: 5

Constraints:

• 2 <= n <= 5000
• nums.length == 2 * n
• 0 <= nums[i] <= 104
• nums contains n + 1 unique elements and one of them is repeated exactly n times.

Solution

class Solution {
public:
  int repeatedNTimes(vector<int>& nums) {
    set<int> st;
    for(auto n : nums) {
      if(st.count(n)) return n;
      st.insert(n);
    }
    return -1;
  }
};

// Accepted
// 103/103 cases passed (0 ms)
// Your runtime beats 100 % of cpp submissions
// Your memory usage beats 96.55 % of cpp submissions (28.3 MB)