refactor 221

Author: fishercoder1534

src/main/java/com/fishercoder/solutions/_221.java

@@ -15,39 +15,33 @@
  */
 public class _221 {
 
-    /**The idea is pretty straightforward: use a 2d dp table to store the intermediate results*/
-    public static int maximalSquare(char[][] matrix) {
-        if (matrix == null || matrix.length == 0) {
-            return 0;
-        }
-        int m = matrix.length;
-        int n = matrix[0].length;
-        int max = Integer.MIN_VALUE;
-        int[][] dp = new int[m][n];
-        for (int i = 0; i < m; i++) {
-            for (int j = 0; j < n; j++) {
-                if (i == 0 || j == 0) {
-                    dp[i][j] = (matrix[i][j] == '1') ? 1 : 0;
-                } else {
-                    if (matrix[i][j] == '0') {
-                        dp[i][j] = 0;
+    public static class Solution1 {
+        /**
+         * The idea is pretty straightforward: use a 2d dp table to store the intermediate results
+         */
+        public int maximalSquare(char[][] matrix) {
+            if (matrix == null || matrix.length == 0) {
+                return 0;
+            }
+            int m = matrix.length;
+            int n = matrix[0].length;
+            int max = Integer.MIN_VALUE;
+            int[][] dp = new int[m][n];
+            for (int i = 0; i < m; i++) {
+                for (int j = 0; j < n; j++) {
+                    if (i == 0 || j == 0) {
+                        dp[i][j] = (matrix[i][j] == '1') ? 1 : 0;
                     } else {
-                        dp[i][j] = Math.min(dp[i - 1][j], Math.min(dp[i][j - 1], dp[i - 1][j - 1])) + 1;
+                        if (matrix[i][j] == '0') {
+                            dp[i][j] = 0;
+                        } else {
+                            dp[i][j] = Math.min(dp[i - 1][j], Math.min(dp[i][j - 1], dp[i - 1][j - 1])) + 1;
+                        }
                     }
+                    max = (max < dp[i][j]) ? dp[i][j] : max;
                 }
-                max = (max < dp[i][j]) ? dp[i][j] : max;
             }
+            return max * max;
         }
-        return max * max;
-    }
-
-    public static void main(String... strings) {
-        char[][] matrix = new char[][]{
-                {'1', '0', '1', '0', '0'},
-                {'1', '0', '1', '1', '1'},
-                {'1', '1', '1', '1', '1'},
-                {'1', '0', '0', '1', '0'},
-        };
-        System.out.println(maximalSquare(matrix));
     }
 }

src/test/java/com/fishercoder/_221Test.java

@@ -0,0 +1,30 @@
+package com.fishercoder;
+
+import com.fishercoder.solutions._221;
+import com.fishercoder.solutions._50;
+import org.junit.BeforeClass;
+import org.junit.Test;
+
+import static org.junit.Assert.assertEquals;
+
+public class _221Test {
+    private static _221.Solution1 solution1;
+    private static char[][] matrix;
+
+    @BeforeClass
+    public static void setup() {
+        solution1 = new _221.Solution1();
+    }
+
+    @Test
+    public void test1() {
+        matrix = new char[][]{
+                {'1', '0', '1', '0', '0'},
+                {'1', '0', '1', '1', '1'},
+                {'1', '1', '1', '1', '1'},
+                {'1', '0', '0', '1', '0'},
+        };
+
+        assertEquals(4, solution1.maximalSquare(matrix));
+    }
+}