Update 0257.二叉树的所有路径.md

Author: sdd-bob

problems/0257.二叉树的所有路径.md

@@ -390,6 +390,8 @@ public:
 
 ```Java
 //解法一
+
+//方式一
 class Solution {
     /**
      * 递归法
@@ -428,9 +430,32 @@ class Solution {
         }
     }
 }
+
+//方式二
+class Solution {
+
+    List<String> result = new ArrayList<>();
+
+    public List<String> binaryTreePaths(TreeNode root) {
+        deal(root, "");
+        return result;
+    }
+
+    public void deal(TreeNode node, String s) {
+        if (node == null)
+            return;
+        if (node.left == null && node.right == null) {
+            result.add(new StringBuilder(s).append(node.val).toString());
+            return;
+        }
+        String tmp = new StringBuilder(s).append(node.val).append("->").toString();
+        deal(node.left, tmp);
+        deal(node.right, tmp);
+    }
+}
 ```
 ```java
-// 解法2
+// 解法二
 class Solution {
     /**
      * 迭代法