intersection-of-multiple-arrays.cpp

// https://leetcode.com/contest/weekly-contest-290/problems/intersection-of-multiple-arrays/

class Solution {
public:
  vector<int> intersection(vector<vector<int>> &nums) {
    map<int, int> mp;
    vector<int> ans;
    for (int i = 0; i < nums.size(); i++) {
      for (int j = 0; j < nums[i].size(); j++) {
        mp[nums[i][j]]++;
      }
    }

    for (auto q : mp) {
      if (q.second == nums.size())
        ans.push_back(q.first);
    }

    return ans;
  }
};