update 129

Author: fishercoder1534

src/main/java/com/fishercoder/solutions/_129.java

@@ -13,11 +13,7 @@ public int sumNumbers(TreeNode root) {
             }
             List<Integer> allNumbers = new ArrayList();
             dfs(root, new StringBuilder(), allNumbers);
-            int sum = 0;
-            for (int i : allNumbers) {
-                sum += i;
-            }
-            return sum;
+            return allNumbers.stream().mapToInt(i -> i).sum();
         }
 
         private void dfs(TreeNode root, StringBuilder sb, List<Integer> allNumbers) {
@@ -31,6 +27,8 @@ private void dfs(TreeNode root, StringBuilder sb, List<Integer> allNumbers) {
             if (root.left == null && root.right == null) {
                 allNumbers.add(Integer.parseInt(sb.toString()));
             }
+            //this is to delete the last value. since it's guaranteed that the value is between [0,9], so only one char needs to be deleted.
+            //however if the value is >= 10 then this approach needs to be adjusted
             sb.deleteCharAt(sb.length() - 1);
         }
     }
@@ -47,7 +45,9 @@ private int dfs(TreeNode root, int sum) {
             if (root.left == null && root.right == null) {
                 return sum * 10 + root.val;
             }
-            return dfs(root.left, sum * 10 + root.val) + dfs(root.right, sum * 10 + root.val);
+            int left = dfs(root.left, sum * 10 + root.val);
+            int right = dfs(root.right, sum * 10 + root.val);
+            return left + right;
         }
     }
 

src/test/java/com/fishercoder/_129Test.java

@@ -0,0 +1,30 @@
+package com.fishercoder;
+
+import com.fishercoder.common.classes.TreeNode;
+import com.fishercoder.common.utils.TreeUtils;
+import com.fishercoder.solutions._129;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+import java.util.Arrays;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+public class _129Test {
+    private static _129.Solution1 solution1;
+    private static _129.Solution2 solution2;
+
+    @BeforeEach
+    public void setup() {
+        solution1 = new _129.Solution1();
+        solution2 = new _129.Solution2();
+    }
+
+    @Test
+    public void test1() {
+        TreeNode root = TreeUtils.constructBinaryTree(Arrays.asList(1, 2, 3));
+        assertEquals(25, (solution1.sumNumbers(root)));
+        assertEquals(25, (solution2.sumNumbers(root)));
+    }
+
+}