[N-0] refactor 114

Author: fishercoder1534

Diff for: src/main/java/com/fishercoder/solutions/_114.java

@@ -3,6 +3,8 @@
 import com.fishercoder.common.classes.TreeNode;
 
 /**
+ * 114. Flatten Binary Tree to Linked List
+ *
  * Given a binary tree, flatten it to a linked list in-place.
 
  For example,
@@ -31,31 +33,21 @@
  */
 public class _114 {
 
-    public void flatten(TreeNode root) {
-        while (root != null) {
-            if (root.left != null) {
-                TreeNode previousNode = root.left;
-                while (previousNode.right != null) {
-                    previousNode = previousNode.right;
+    public static class Solution1 {
+        public void flatten(TreeNode root) {
+            while (root != null) {
+                if (root.left != null) {
+                    TreeNode previousNode = root.left;
+                    while (previousNode.right != null) {
+                        previousNode = previousNode.right;
+                    }
+                    previousNode.right = root.right;
+                    root.right = root.left;
+                    root.left = null;
                 }
-                previousNode.right = root.right;
-                root.right = root.left;
-                root.left = null;
+                root = root.right;
             }
-            root = root.right;
         }
     }
 
-    public static void main(String... args) {
-        TreeNode root = new TreeNode(1);
-        root.left = new TreeNode(2);
-        root.left.left = new TreeNode(3);
-        root.left.right = new TreeNode(4);
-        root.right = new TreeNode(5);
-        root.right.right = new TreeNode(6);
-
-        _114 test = new _114();
-        test.flatten(root);
-    }
-
-}
+}

Diff for: src/test/java/com/fishercoder/_114Test.java

@@ -0,0 +1,28 @@
+package com.fishercoder;
+
+import com.fishercoder.common.classes.TreeNode;
+import com.fishercoder.common.utils.TreeUtils;
+import com.fishercoder.solutions._114;
+import org.junit.BeforeClass;
+import org.junit.Test;
+
+import java.util.Arrays;
+
+public class _114Test {
+    private static _114.Solution1 solution1;
+    private static TreeNode root;
+
+    @BeforeClass
+    public static void setup() {
+        solution1 = new _114.Solution1();
+    }
+
+    @Test
+    public void test1() {
+        root = TreeUtils.constructBinaryTree(Arrays.asList(1, 2, 5, 3, 4, null, 6));
+        TreeUtils.printBinaryTree(root);
+        solution1.flatten(root);
+        TreeUtils.printBinaryTree(root);
+    }
+
+}