Add solution and test-cases for problem 997

Author: 0xff-dev

leetcode/901-1000/0997.Find-the-Town-Judge/README.md

@@ -1,29 +1,37 @@
 # [997.Find the Town Judge][title]
 
-> [!WARNING|style:flat]
-> This question is temporarily unanswered if you have good ideas. Welcome to [Create Pull Request PR](https://github.com/kylesliu/awesome-golang-algorithm)
-
 ## Description
+In a town, there are `n` people labeled from `1` to `n`. There is a rumor that one of these people is secretly the town judge.
 
-**Example 1:**
+If the town judge exists, then: 
 
-```
-Input: a = "11", b = "1"
-Output: "100"
-```
+1. The town judge trusts nobody.
+2. Everybody (except for the town judge) trusts the town judge.
+3. There is exactly one person that satisfies properties **1** and **2**. 
+
+You are given an array `trust` where `trust[i] = [ai, bi]` representing that the person labeled a<sub>i</sub> trusts the person labeled b<sub>i</sub>.
+
+Return the label of the town judge if the town judge exists and can be identified, or return `-1` otherwise. 
 
-## 题意
-> ...
 
-## 题解
+**Example 1:**
 
-### 思路1
-> ...
-Find the Town Judge
-```go
+```
+Input: n = 2, trust = [[1,2]]
+Output: 2
 ```
 
+**Example 2:**
+```
+Input: n = 3, trust = [[1,3],[2,3]]
+Output: 3
+```
 
+**Example 3:**
+```
+Input: n = 3, trust = [[1,3],[2,3],[3,1]]
+Output: -1
+```
 ## 结语
 
 如果你同我一样热爱数据结构、算法、LeetCode，可以关注我 GitHub 上的 LeetCode 题解：[awesome-golang-algorithm][me]

leetcode/901-1000/0997.Find-the-Town-Judge/Solution.go

@@ -1,5 +1,16 @@
 package Solution
 
-func Solution(x bool) bool {
-return x
+func Solution(n int, trust [][]int) int {
+ab, ba := make([]int, n+1), make([]int, n+1)
+for _, t := range trust {
+a, b := t[0], t[1]
+ab[a]++
+ba[b]++
+}
+for p := 1; p <= n; p++ {
+if ab[p] == 0 && ba[p] == n-1 {
+return p
+}
+}
+return -1
 }

leetcode/901-1000/0997.Find-the-Town-Judge/Solution_test.go

@@ -10,18 +10,19 @@ func TestSolution(t *testing.T) {
 //	测试用例
 cases := []struct {
 name string
-inputs bool
-expect bool
+n int
+inputs [][]int
+expect int
 }{
-{"TestCase", true, true},
-{"TestCase", true, true},
-{"TestCase", false, false},
+{"TestCase1", 2, [][]int{{1, 2}}, 2},
+{"TestCase2", 3, [][]int{{1, 3}, {2, 3}}, 3},
+{"TestCase3", 3, [][]int{{1, 3}, {2, 3}, {3, 1}}, -1},
 }
 
 //	开始测试
 for i, c := range cases {
 t.Run(c.name+" "+strconv.Itoa(i), func(t *testing.T) {
-got := Solution(c.inputs)
+got := Solution(c.n, c.inputs)
 if !reflect.DeepEqual(got, c.expect) {
 t.Fatalf("expected: %v, but got: %v, with inputs: %v",
 c.expect, got, c.inputs)