Description

Submission

class Solution {
public:
    vector<int> smallestRange(vector<vector<int>>& nums) {
        set<pair<int,int>> Set;
        int n = nums.size();
        vector<int> pointers(n, 0);

        for(int i = 0; i < n; ++i) {
            Set.insert({nums[i][0], i});
        }

        int r = INT_MAX;
        vector<int> ret;
        while(true) {
            if(Set.rbegin()->first - Set.begin()->first < r) {
                r = Set.rbegin()->first - Set.begin()->first;
                ret = {Set.begin()->first, Set.rbegin()->first};
            }
            int i = Set.begin()->second;
            pointers[i]++;
            if(pointers[i] == nums[i].size()) break;
            Set.erase(Set.begin());
            Set.insert({nums[i][pointers[i]], i});
        }
        return ret;
    }
};