refactor 62

Author: fishercoder1534

src/main/java/com/fishercoder/solutions/_62.java

@@ -1,63 +1,34 @@
 package com.fishercoder.solutions;
 
-import com.fishercoder.common.utils.CommonUtils;
-
-/**Unique Paths
+/**
+ * 62. Unique Paths
 
 A robot is located at the top-left corner of a m x n grid (marked 'Start' in the diagram below).
 The robot can only move either down or right at any point in time. The robot is trying to reach
 the bottom-right corner of the grid (marked 'Finish' in the diagram below).
 
-How many possible unique paths are there?*/
+How many possible unique paths are there?
+ */
 public class _62 {
-    
-    /**Another typical DP question, use a 2d array:
-     * the first row and the first column need to be initialized to be 1 since there's only one way to reach every
-     * position in the first row and the first column: either from left or top.*/
-    public int uniquePaths(int m, int n) {
-        int[][] dp = new int[m][n];
-        for (int i = 0; i < m; i++) {
-            dp[i][0] = 1;
-        }
-        for (int i = 0; i < n; i++) {
-            dp[0][i] = 1;
-        }
-
-        for (int i = 1; i < m; i++) {
-            for (int j = 1; j < n; j++) {
-                int ways = 0;
-                if (i - 1 >= 0) {
-                    ways += dp[i - 1][j];
-                }
-                if (j - 1 >= 0) {
-                    ways += dp[i][j - 1];
-                }
-                dp[i][j] = ways;
-            }
-        }
-        CommonUtils.printMatrix(dp);
-        return dp[m - 1][n - 1];
-    }
 
-    //and we can actually put the two initialization for loop into the one
-    public int uniquePaths_merged_for_loop(int m, int n) {
-        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] = 1;
-                } else {
-                    dp[i][j] = dp[i - 1][j] + dp[i][j - 1];
-                }
-            }
+  public static class Solution1 {
+    /**
+     * Another typical DP question, use a 2d array: the first row and the first column need to be
+     * initialized to be 1 since there's only one way to reach every position in the first row and
+     * the first column: either from left or top.
+     */
+    public int uniquePaths(int m, int n) {
+      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] = 1;
+          } else {
+            dp[i][j] = dp[i - 1][j] + dp[i][j - 1];
+          }
         }
-        return dp[m - 1][n - 1];
-    }
-
-    public static void main(String... strings) {
-        _62 test = new _62();
-        int m = 1;
-        int n = 2;
-        System.out.println(test.uniquePaths(m, n));
+      }
+      return dp[m - 1][n - 1];
     }
+  }
 }

src/test/java/com/fishercoder/_62Test.java

@@ -0,0 +1,21 @@
+package com.fishercoder;
+
+import com.fishercoder.solutions._62;
+import org.junit.BeforeClass;
+import org.junit.Test;
+
+import static junit.framework.Assert.assertEquals;
+
+public class _62Test {
+  private static _62.Solution1 solution1;
+
+  @BeforeClass
+  public static void setup() {
+    solution1 = new _62.Solution1();
+  }
+
+  @Test
+  public void test1() {
+    assertEquals(1, solution1.uniquePaths(1, 2));
+  }
+}