You are given an integer array matches where matches[i] = [winneri, loseri] indicates that the player winneri defeated player loseri in a match.
Return a list answer of size 2 where:
answer[0] is a list of all players that have not lost any matches.answer[1] is a list of all players that have lost exactly one match.The values in the two lists should be returned in increasing order.
Note:
Example 1:
Input: matches = [[1,3],[2,3],[3,6],[5,6],[5,7],[4,5],[4,8],[4,9],[10,4],[10,9]] Output: [[1,2,10],[4,5,7,8]] Explanation: Players 1, 2, and 10 have not lost any matches. Players 4, 5, 7, and 8 each have lost one match. Players 3, 6, and 9 each have lost two matches. Thus, answer[0] = [1,2,10] and answer[1] = [4,5,7,8].
Example 2:
Input: matches = [[2,3],[1,3],[5,4],[6,4]] Output: [[1,2,5,6],[]] Explanation: Players 1, 2, 5, and 6 have not lost any matches. Players 3 and 4 each have lost two matches. Thus, answer[0] = [1,2,5,6] and answer[1] = [].
Constraints:
1 <= matches.length <= 105matches[i].length == 21 <= winneri, loseri <= 105winneri != loserimatches[i] are unique.class Solution {
public:
vector<vector<int>> findWinners(vector<vector<int>>& matches) {
vector<vector<int>> ans(2, vector<int>({}));
unordered_map <int, pair<int, int>> m;
for (vector<int> v: matches)
m[v[0]].first++, m[v[1]].second++;
for (auto [K,P]:m){
if(P.first+P.second==0) // no matches played
continue;
else if (P.second==1)
ans[1].push_back(K);
else if (P.second==0)
ans[0].push_back(K);
}
sort(begin(ans[0]), end(ans[0]));
sort(begin(ans[1]), end(ans[1]));
return ans;
}
};