# 2225. Find Players With Zero or One Losses

Medium
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` is a list of all players that have not lost any matches.
• `answer` 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.
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.
Constraints:
• `1 <= matches.length <= 105`
• `matches[i].length == 2`
• `1 <= winneri, loseri <= 105`
• `winneri != loseri`
• All `matches[i]` are unique.

### 解題

func findWinners(matches [][]int) [][]int {
m := make(map[int]int)
v := make(map[int]bool)
for _, match := range matches {
m[match]++
v[match] = true
v[match] = true
}
res := [][]int{}
res = append(res, []int{})
res = append(res, []int{})
for k := range v {
if m[k] == 0 {
res = append(res, k)
} else if m[k] == 1 {
res = append(res, k)
}
}
sort.Ints(res)
sort.Ints(res)
return res
}