📝 docs : add 257. Binary Tree Paths.md

Author: GoogTech

docs/LeetCod刷题之旅及题目解析/257.二叉树的所有路径/257.二叉树的所有路径.md

@@ -0,0 +1,107 @@
+## 257. 二叉树的所有路径
+> https://leetcode-cn.com/problems/binary-tree-paths/
+
+
+### Java
+```java
+/*
+ * @Author: Goog Tech
+ * @Date: 2020-08-16 17:00:50
+ * @LastEditTime: 2020-08-16 17:11:57
+ * @Description: https://leetcode-cn.com/problems/binary-tree-paths/
+ * @FilePath: \leetcode-googtech\#102. Binary Tree Level Order Traversal\257.二叉树的所有路径.java
+ * @WebSite: https://algorithm.show/
+ */
+
+/*
+ * @lc app=leetcode.cn id=257 lang=java
+ *
+ * [257] 二叉树的所有路径
+ */
+
+// @lc code=start
+/**
+ * Definition for a binary tree node.
+ * public class TreeNode {
+ *     int val;
+ *     TreeNode left;
+ *     TreeNode right;
+ *     TreeNode(int x) { val = x; }
+ * }
+ */
+class Solution {
+
+    public List<String> binaryTreePaths(TreeNode root) {
+        LinkedList<String> paths = new LinkedList<>();
+        getPaths(root, "", paths);
+        return paths;
+    }
+
+    private void getPaths(TreeNode root, String path, LinkedList<String> paths) {
+        if(root !=null) {
+            // 记录当前节点到叶子节点的路径
+            path += Integer.toString(root.val);
+            // 判断当前节点是否为叶子节点,若是则将其整体添加到 List 集合中
+            if(root.left == null && root.right == null) {
+                paths.add(path);
+            // 反之则继续遍历当前节点的左右孩子节点
+            }else {
+                path += "->";
+                getPaths(root.left, path, paths);
+                getPaths(root.right, path, paths);
+            }
+        }
+    }
+}
+// @lc code=end
+```
+
+### Python
+```python
+'''
+Author: Goog Tech
+Date: 2020-08-16 16:58:35
+LastEditTime: 2020-08-16 17:10:50
+Description: https://leetcode-cn.com/problems/binary-tree-paths/
+FilePath: \leetcode-googtech\#102. Binary Tree Level Order Traversal\257.二叉树的所有路径.py
+WebSite: https://algorithm.show/
+'''
+#
+# @lc app=leetcode.cn id=257 lang=python
+#
+# [257] 二叉树的所有路径
+#
+
+# @lc code=start
+# Definition for a binary tree node.
+# class TreeNode(object):
+#     def __init__(self, x):
+#         self.val = x
+#         self.left = None
+#         self.right = None
+
+class Solution(object):
+    def binaryTreePaths(self, root):
+        """
+        :type root: TreeNode
+        :rtype: List[str]
+        """
+        # 判断当前节点是否为空
+        if not root: 
+            return []
+        # 判断当前节点是否为叶子节点
+        if not root.left and not root.right: 
+            return [str(root.val)]
+        # 初始化用于存储根节点到左右叶子节点路径的列表
+        paths = []
+        # 递归添加当前节点到叶子节点的路径
+        if root.left:
+            for i in self.binaryTreePaths(root.left):
+                paths.append(str(root.val) + '->' + i)
+        if root.right:
+            for i in self.binaryTreePaths(root.right):
+                paths.append(str(root.val) + '->' + i)
+        # 返回结果
+        return paths
+# @lc code=end
+```

docs/SUMMARY.md

@@ -56,6 +56,7 @@
     * [232.用栈实现队列](LeetCod刷题之旅及题目解析/232.用栈实现队列/232.用栈实现队列.md)
     * [234.回文链表](LeetCod刷题之旅及题目解析/234.回文链表/234.回文链表.md)
     * [237.删除链表中的节点](LeetCod刷题之旅及题目解析/237.删除链表中的节点/237.删除链表中的节点.md)
+    * [257.二叉树的所有路径](LeetCod刷题之旅及题目解析/257.二叉树的所有路径/257.二叉树的所有路径.md)
     * [258.各位相加](LeetCod刷题之旅及题目解析/258.各位相加/258.各位相加.md)
     * [283.移动零](LeetCod刷题之旅及题目解析/283.移动零/283.移动零.md)
     * [344.反转字符串](LeetCod刷题之旅及题目解析/344.反转字符串/344.反转字符串.md)