O(n) space and O(nlogn) time using hashmap and sorting.

Author: 149ps

2225. Find Players With Zero or One Losses/2225. Find Players With Zero or One Losses.py

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+"""
+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.
+"""
+class Solution:
+    def findWinners(self, matches: List[List[int]]) -> List[List[int]]:
+        hmap = collections.OrderedDict()
+        for match in matches:
+            hmap[match[1]] = hmap.get(match[1],0) + 1
+            if match[0] not in hmap: hmap[match[0]] = 0
+        result = []
+        temp1,temp2 = [],[]
+        for k,v in hmap.items():
+            if v == 0:
+                temp1.append(k)
+            if v == 1:
+                temp2.append(k)
+        result.append(sorted(temp1))
+        result.append(sorted(temp2))
+        return result