add a solution for 997

Author: fishercoder1534

src/main/java/com/fishercoder/solutions/_997.java

@@ -5,20 +5,42 @@
 
 public class _997 {
     public static class Solution1 {
-        public int findJudge(int N, int[][] trust) {
-            int[] trustPoints = new int[N];
+        public int findJudge(int n, int[][] trust) {
+            int[] trustPoints = new int[n];
             Set<Integer> trustOthers = new HashSet<>();
             for (int[] eachTrust : trust) {
                 trustPoints[eachTrust[1] - 1]++;
                 trustOthers.add(eachTrust[0]);
             }
             int judge = -1;
             for (int i = 0; i < trustPoints.length; i++) {
-                if (trustPoints[i] == N - 1 && !trustOthers.contains(i + 1)) {
+                if (trustPoints[i] == n - 1 && !trustOthers.contains(i + 1)) {
                     judge = i + 1;
                 }
             }
             return judge;
         }
     }
+
+    public static class Solution2 {
+        /**
+         * Credit: https://leetcode.com/problems/find-the-town-judge/solution/ solution 2
+         */
+        public int findJudge(int n, int[][] trust) {
+            if (trust.length < n - 1) {
+                return -1;
+            }
+            int[] trustScores = new int[n];
+            for (int[] t : trust) {
+                trustScores[t[1] - 1]++;
+                trustScores[t[0] - 1]--;
+            }
+            for (int i = 0; i < n; i++) {
+                if (trustScores[i] == n - 1) {
+                    return i + 1;
+                }
+            }
+            return -1;
+        }
+    }
 }

src/test/java/com/fishercoder/_997Test.java

@@ -7,47 +7,50 @@
 import static org.junit.Assert.assertEquals;
 
 public class _997Test {
-  private static _997.Solution1 solution1;
-  private static int[][] trust;
-
-  @BeforeClass
-  public static void setup() {
-    solution1 = new _997.Solution1();
-  }
-
-  @Test
-  public void test1() {
-    trust = new int[][] {{1, 2}};
-    assertEquals(2, solution1.findJudge(2, trust));
-  }
-
-  @Test
-  public void test2() {
-    trust = new int[][] {{1, 3}, {2, 3}};
-    assertEquals(3, solution1.findJudge(3, trust));
-  }
-
-  @Test
-  public void test3() {
-    trust = new int[][] {{1, 2}, {2, 3}, {3, 1}};
-    assertEquals(-1, solution1.findJudge(3, trust));
-  }
-
-  @Test
-  public void test4() {
-    trust = new int[][] {{1, 2}, {2, 3}};
-    assertEquals(-1, solution1.findJudge(3, trust));
-  }
-
-  @Test
-  public void test5() {
-    trust = new int[][] {{1, 3}, {1, 4}, {2, 3}, {2, 4}, {4, 3}};
-    assertEquals(3, solution1.findJudge(4, trust));
-  }
-
-  @Test
-  public void test6() {
-    trust = new int[][] {{1, 3}, {2, 3}, {3, 1}};
-    assertEquals(-1, solution1.findJudge(3, trust));
-  }
+    private static _997.Solution1 solution1;
+    private static _997.Solution2 solution2;
+    private static int[][] trust;
+
+    @BeforeClass
+    public static void setup() {
+        solution1 = new _997.Solution1();
+        solution2 = new _997.Solution2();
+    }
+
+    @Test
+    public void test1() {
+        trust = new int[][]{{1, 2}};
+        assertEquals(2, solution1.findJudge(2, trust));
+        assertEquals(2, solution2.findJudge(2, trust));
+    }
+
+    @Test
+    public void test2() {
+        trust = new int[][]{{1, 3}, {2, 3}};
+        assertEquals(3, solution1.findJudge(3, trust));
+    }
+
+    @Test
+    public void test3() {
+        trust = new int[][]{{1, 2}, {2, 3}, {3, 1}};
+        assertEquals(-1, solution1.findJudge(3, trust));
+    }
+
+    @Test
+    public void test4() {
+        trust = new int[][]{{1, 2}, {2, 3}};
+        assertEquals(-1, solution1.findJudge(3, trust));
+    }
+
+    @Test
+    public void test5() {
+        trust = new int[][]{{1, 3}, {1, 4}, {2, 3}, {2, 4}, {4, 3}};
+        assertEquals(3, solution1.findJudge(4, trust));
+    }
+
+    @Test
+    public void test6() {
+        trust = new int[][]{{1, 3}, {2, 3}, {3, 1}};
+        assertEquals(-1, solution1.findJudge(3, trust));
+    }
 }