refactor 417

fishercoder1534 · fishercoder1534 · commit eef5bff3ed11 · 2019-03-18T02:04:12.000-07:00
diff --git a/src/main/java/com/fishercoder/solutions/_417.java b/src/main/java/com/fishercoder/solutions/_417.java
@@ -2,7 +2,10 @@
 
 import java.util.ArrayList;
 import java.util.List;
-/**Given the following 5x5 matrix:
+/**
+ * 417. Pacific Atlantic Water Flow
+ *
+ * Given the following 5x5 matrix:
 
   Pacific ~   ~   ~   ~   ~ 
        ~  1   2   2   3  (5) *
@@ -17,86 +20,57 @@
 [[0, 4], [1, 3], [1, 4], [2, 2], [3, 0], [3, 1], [4, 0]] (positions with parentheses in above matrix).*/
 
 public class _417 {
-    //looked at this post: https://discuss.leetcode.com/topic/62379/java-bfs-dfs-from-ocean
-
-    /**
-     * One typical trick to work on 2d grid problems is to go through the border and put proper ones into a queue if using BFS.
-     */
-    public List<int[]> pacificAtlantic(int[][] matrix) {
-
-        List<int[]> result = new ArrayList();
-        if (matrix == null || matrix.length == 0 || matrix[0].length == 0) {
-            return result;
-        }
+    public static class Solution1 {
+        /**
+         * Credit: looked at this post: https://discuss.leetcode.com/topic/62379/java-bfs-dfs-from-ocean
+         * <p>
+         * One typical trick to work on 2d grid problems is to go through the border and put proper ones into a queue if using BFS.
+         */
+        public List<int[]> pacificAtlantic(int[][] matrix) {
+
+            List<int[]> result = new ArrayList();
+            if (matrix == null || matrix.length == 0 || matrix[0].length == 0) {
+                return result;
+            }
 
-        int m = matrix.length;
-        int n = matrix[0].length;
-        boolean[][] pacific = new boolean[m][n];
-        boolean[][] atlantic = new boolean[m][n];
+            int m = matrix.length;
+            int n = matrix[0].length;
+            boolean[][] pacific = new boolean[m][n];
+            boolean[][] atlantic = new boolean[m][n];
 
-        for (int i = 0; i < m; i++) {
-            dfs(matrix, pacific, Integer.MIN_VALUE, i, 0);
-            dfs(matrix, atlantic, Integer.MIN_VALUE, i, n - 1);
-        }
+            for (int i = 0; i < m; i++) {
+                dfs(matrix, pacific, Integer.MIN_VALUE, i, 0);
+                dfs(matrix, atlantic, Integer.MIN_VALUE, i, n - 1);
+            }
 
-        for (int i = 0; i < n; i++) {
-            dfs(matrix, pacific, Integer.MIN_VALUE, 0, i);
-            dfs(matrix, atlantic, Integer.MIN_VALUE, m - 1, i);
-        }
+            for (int i = 0; i < n; i++) {
+                dfs(matrix, pacific, Integer.MIN_VALUE, 0, i);
+                dfs(matrix, atlantic, Integer.MIN_VALUE, m - 1, i);
+            }
 
-        for (int i = 0; i < m; i++) {
-            for (int j = 0; j < n; j++) {
-                if (pacific[i][j] && atlantic[i][j]) {
-                    result.add(new int[]{i, j});
+            for (int i = 0; i < m; i++) {
+                for (int j = 0; j < n; j++) {
+                    if (pacific[i][j] && atlantic[i][j]) {
+                        result.add(new int[]{i, j});
+                    }
                 }
             }
-        }
-
-        return result;
-    }
 
-    void dfs(int[][] matrix, boolean[][] visited, int height, int x, int y) {
-        int m = matrix.length;
-        int n = matrix[0].length;
-        if (x < 0 || y < 0 || x >= m || y >= n || matrix[x][y] < height || visited[x][y]) {
-            return;
+            return result;
         }
-        visited[x][y] = true;
-        dfs(matrix, visited, matrix[x][y], x + 1, y);
-        dfs(matrix, visited, matrix[x][y], x, y + 1);
-        dfs(matrix, visited, matrix[x][y], x - 1, y);
-        dfs(matrix, visited, matrix[x][y], x, y - 1);
-    }
 
-    public static void main(String... args) {
-        _417 test = new _417();
-//        int[][] matrix = new int[][]{
-//                {1,2,2,3,5},
-//                {3,2,3,4,4},
-//                {2,4,5,3,1},
-//                {6,7,1,4,5},
-//                {5,1,1,2,4},
-//        };
-
-//        int[][] matrix = new int[][]{//this one is correct
-//                {3,5},
-//                {4,4},
-//        };
-
-//        int[][] matrix = new int[][]{//this one is correct
-//                {2,3,5},
-//                {3,4,4},
-//        };
-
-        int[][] matrix = new int[][]{
-                {2, 3, 5},
-                {3, 4, 4},
-                {5, 3, 1},
-        };
-        List<int[]> result = test.pacificAtlantic(matrix);
-        for (int[] point : result) {
-            System.out.println(point[0] + "\t" + point[1]);
+        void dfs(int[][] matrix, boolean[][] visited, int height, int x, int y) {
+            int m = matrix.length;
+            int n = matrix[0].length;
+            if (x < 0 || y < 0 || x >= m || y >= n || matrix[x][y] < height || visited[x][y]) {
+                return;
+            }
+            visited[x][y] = true;
+            dfs(matrix, visited, matrix[x][y], x + 1, y);
+            dfs(matrix, visited, matrix[x][y], x, y + 1);
+            dfs(matrix, visited, matrix[x][y], x - 1, y);
+            dfs(matrix, visited, matrix[x][y], x, y - 1);
         }
     }
 
-}
+}
diff --git a/src/test/java/com/fishercoder/_417Test.java b/src/test/java/com/fishercoder/_417Test.java
@@ -0,0 +1,65 @@
+package com.fishercoder;
+
+import com.fishercoder.common.utils.CommonUtils;
+import com.fishercoder.solutions._417;
+import org.junit.BeforeClass;
+import org.junit.Test;
+
+public class _417Test {
+    private static _417.Solution1 solution1;
+    private static int[][] matrix;
+
+    @BeforeClass
+    public static void setup() {
+        solution1 = new _417.Solution1();
+    }
+
+    @Test
+    public void test1() {
+        matrix = new int[][]{
+                {2, 3, 5},
+                {3, 4, 4},
+                {5, 3, 1},
+        };
+        for (int[] arr : solution1.pacificAtlantic(matrix)) {
+            CommonUtils.printArray(arr);
+        }
+    }
+
+    @Test
+    public void test2() {
+        matrix = new int[][]{
+                {3, 5},
+                {4, 4},
+        };
+        for (int[] arr : solution1.pacificAtlantic(matrix)) {
+            CommonUtils.printArray(arr);
+        }
+    }
+
+    @Test
+    public void test3() {
+        matrix = new int[][]{
+                {1, 2, 2, 3, 5},
+                {3, 2, 3, 4, 4},
+                {2, 4, 5, 3, 1},
+                {6, 7, 1, 4, 5},
+                {5, 1, 1, 2, 4},
+        };
+        for (int[] arr : solution1.pacificAtlantic(matrix)) {
+            CommonUtils.printArray(arr);
+        }
+    }
+
+    @Test
+    public void test4() {
+        matrix = new int[][]{
+                {2, 3, 5},
+                {3, 4, 4},
+        };
+        for (int[] arr : solution1.pacificAtlantic(matrix)) {
+            CommonUtils.printArray(arr);
+        }
+    }
+
+}
