2225. Find Players With Zero or One Losses

Description

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:

• You should only consider the players that have played at least one match.
• The testcases will be generated such that no two matches will have the same outcome.

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 <= 105
• matches[i].length == 2
• 1 <= winneri, loseri <= 105
• winneri != loseri
• All matches[i] are unique.

Solutions

• class Solution {
public List<List<Integer>> findWinners(int[][] matches) {
Map<Integer, Integer> cnt = new HashMap<>();
for (int[] m : matches) {
int a = m[0], b = m[1];
cnt.putIfAbsent(a, 0);
cnt.put(b, cnt.getOrDefault(b, 0) + 1);
}
List<List<Integer>> ans = new ArrayList<>();
for (Map.Entry<Integer, Integer> entry : cnt.entrySet()) {
int u = entry.getKey();
int v = entry.getValue();
if (v < 2) {
}
}
Collections.sort(ans.get(0));
Collections.sort(ans.get(1));
return ans;
}
}

• class Solution {
public:
vector<vector<int>> findWinners(vector<vector<int>>& matches) {
unordered_map<int, int> cnt;
for (auto& m : matches) {
int a = m[0], b = m[1];
if (!cnt.count(a)) cnt[a] = 0;
++cnt[b];
}
vector<vector<int>> ans(2);
for (auto& [u, v] : cnt) {
if (v < 2) ans[v].push_back(u);
}
sort(ans[0].begin(), ans[0].end());
sort(ans[1].begin(), ans[1].end());
return ans;
}
};

• class Solution:
def findWinners(self, matches: List[List[int]]) -> List[List[int]]:
cnt = Counter()
for a, b in matches:
if a not in cnt:
cnt[a] = 0
cnt[b] += 1
ans = [[], []]
for u, v in cnt.items():
if v < 2:
ans[v].append(u)
ans[0].sort()
ans[1].sort()
return ans


• func findWinners(matches [][]int) [][]int {
cnt := map[int]int{}
for _, m := range matches {
a, b := m[0], m[1]
if _, ok := cnt[a]; !ok {
cnt[a] = 0
}
cnt[b]++
}
ans := make([][]int, 2)
for u, v := range cnt {
if v < 2 {
ans[v] = append(ans[v], u)
}
}
sort.Ints(ans[0])
sort.Ints(ans[1])
return ans
}

• function findWinners(matches: number[][]): number[][] {
const cnt: Map<number, number> = new Map();
for (const [a, b] of matches) {
cnt.set(a, cnt.has(a) ? cnt.get(a) : 0);
cnt.set(b, (cnt.get(b) || 0) + 1);
}
const ans: number[][] = [[], []];
for (let [u, v] of cnt.entries()) {
if (v < 2) {
ans[v].push(u);
}
}
ans[0].sort((a, b) => a - b);
ans[1].sort((a, b) => a - b);
return ans;
}


• /**
* @param {number[][]} matches
* @return {number[][]}
*/
var findWinners = function (matches) {
const cnt = new Map();
for (const [a, b] of matches) {
cnt.set(a, cnt.has(a) ? cnt.get(a) : 0);
cnt.set(b, (cnt.get(b) || 0) + 1);
}
const ans = [[], []];
for (let [u, v] of cnt.entries()) {
if (v < 2) {
ans[v].push(u);
}
}
ans[0].sort((a, b) => a - b);
ans[1].sort((a, b) => a - b);
return ans;
};