Update 129.sum-root-to-leaf-numbers.md

Author: daydaygo

problems/129.sum-root-to-leaf-numbers.md

@@ -74,7 +74,7 @@ https://leetcode-cn.com/problems/sum-root-to-leaf-numbers/
 
 ## 代码
 
-* 语言支持：JS，C++，Python
+* 语言支持：JS，C++，Python, Go, PHP
 
 JavaScipt Code：
 
@@ -168,6 +168,79 @@ class Solution:
         return helper(root, 0)
 ```
 
+Go Code:
+
+```go
+/**
+ * Definition for a binary tree node.
+ * type TreeNode struct {
+ *     Val int
+ *     Left *TreeNode
+ *     Right *TreeNode
+ * }
+ */
+func sumNumbers(root *TreeNode) int {
+	return helper(root, 0)
+}
+
+func helper(root *TreeNode, cur int) int {
+	if root == nil {
+		return 0 // 当前非叶子节点, 不计算
+	}
+
+	next := cur*10 + root.Val
+	if root.Left == nil && root.Right == nil {
+		return next // 当前为叶子节点, 计算
+	}
+
+	l := helper(root.Left, next)
+	r := helper(root.Right, next)
+	return l + r
+}
+```
+
+PHP Code:
+
+```php
+/**
+ * Definition for a binary tree node.
+ * class TreeNode {
+ *     public $val = null;
+ *     public $left = null;
+ *     public $right = null;
+ *     function __construct($value) { $this->val = $value; }
+ * }
+ */
+class Solution
+{
+
+    /**
+     * @param TreeNode $root
+     * @return Integer
+     */
+    function sumNumbers($root)
+    {
+        return (new Solution())->helper($root, 0);
+    }
+
+    /**
+     * @param TreeNode $root
+     * @param int $cur
+     * @return int
+     */
+    function helper($root, $cur)
+    {
+        if (!$root) return 0; // 当前不是叶子节点
+        $next = $cur * 10 + $root->val;
+        if (!$root->left && !$root->right) return $next; // 当前为叶子节点, 返回叶子节点的值
+
+        $l = (new Solution())->helper($root->left, $next);
+        $r = (new Solution())->helper($root->right, $next);
+        return $l + $r;
+    }
+}
+```
+
 **复杂度分析**
 
 - 时间复杂度：$O(N)$