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257. Binary Tree Paths

String Backtracking Tree Depth-First Search Binary Tree

Problem - Binary Tree Paths

Easy

Given the root of a binary tree, return all root-to-leaf paths in any order.

A leaf is a node with no children.

 

Example 1:

Input: root = [1,2,3,null,5]
Output: ["1->2->5","1->3"]

Example 2:

Input: root = [1]
Output: ["1"]

 

Constraints:

  • The number of nodes in the tree is in the range [1, 100].
  • -100 <= Node.val <= 100

Solutions

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# Definition for a binary tree node.
# class TreeNode:
#     def __init__(self, val=0, left=None, right=None):
#         self.val = val
#         self.left = left
#         self.right = right
class Solution:
    def binaryTreePaths(self, root: Optional[TreeNode]) -> List[str]:
        result = []
        temp = []
        def dfs(root: Optional[TreeNode]):
            if root is None:
                return
            temp.append(str(root.val))
            if root.left is None and root.right is None:
                result.append("->".join(temp))
            else:
                dfs(root.left)
                dfs(root.right)
            temp.pop()

        dfs(root)
        return result

Submission Stats:

  • Runtime: 0 ms (100.00%)
  • Memory: 17.8 MB (44.24%)