Merge pull request #476 from openset/develop

Add: Find the Town Judge

Author: Shuo

problems/find-the-town-judge/find_the_town_judge.go

@@ -0,0 +1,16 @@
+package find_the_town_judge
+
+func findJudge(N int, trust [][]int) int {
+	ans, count := 1, make([]int, N+1)
+	for _, t := range trust {
+		count[t[0]] = N
+		count[t[1]]++
+		if count[t[1]] == N-1 {
+			ans = t[1]
+		}
+		if ans == t[0] {
+			ans = -1
+		}
+	}
+	return ans
+}

problems/find-the-town-judge/find_the_town_judge_test.go

@@ -0,0 +1,68 @@
+package find_the_town_judge
+
+import "testing"
+
+type caseType struct {
+	N        int
+	trust    [][]int
+	expected int
+}
+
+func TestFindJudge(t *testing.T) {
+	tests := [...]caseType{
+		{
+			N: 2,
+			trust: [][]int{
+				{1, 2},
+			},
+			expected: 2,
+		},
+		{
+			N: 3,
+			trust: [][]int{
+				{1, 3},
+				{2, 3},
+			},
+			expected: 3,
+		},
+		{
+			N: 3,
+			trust: [][]int{
+				{1, 3},
+				{2, 3},
+				{3, 1},
+			},
+			expected: -1,
+		},
+		{
+			N: 3,
+			trust: [][]int{
+				{1, 2},
+				{2, 3},
+			},
+			expected: -1,
+		},
+		{
+			N: 4,
+			trust: [][]int{
+				{1, 3},
+				{1, 4},
+				{2, 3},
+				{2, 4},
+				{4, 3},
+			},
+			expected: 3,
+		},
+		{
+			N:        1,
+			trust:    [][]int{},
+			expected: 1,
+		},
+	}
+	for _, tc := range tests {
+		output := findJudge(tc.N, tc.trust)
+		if output != tc.expected {
+			t.Fatalf("input: %v %v, output: %v, expected: %v", tc.N, tc.trust, output, tc.expected)
+		}
+	}
+}