Practice/Bloomberg/Leetcode 257. Binary Tree Paths

Leetcode 257. Binary Tree Paths

CodingMust

Problem

Given the root of a binary tree, return all paths from the root node to every leaf node in the tree. Each path should be represented as a string with node values separated by "->".

A leaf node is defined as a node with no children (both left and right pointers are null).

Requirements

1. Return an array of strings, where each string represents one complete path from root to leaf
2. Format each path as node values joined with "->" (e.g., "1->2->5")
3. The order of paths in the result array does not matter
4. Handle edge cases like empty trees and single-node trees

Constraints

• The number of nodes in the tree is in the range [0, 100]
• -100 ≤= Node.val ≤= 100
• Each node value can be any integer (including negative numbers)

Examples

Example 1:

` Input: 1 /
2 3 /
5 6

Output: ["1->2->5", "1->2->6", "1->3"]

Explanation: There are three leaf nodes (5, 6, and 3). The paths from root to each leaf are:

• 1 to 2 to 5: "1->2->5"
• 1 to 2 to 6: "1->2->6"
• 1 to 3: "1->3" `

Example 2:

` Input: 1

Output: ["1"]

Explanation: The tree has only one node, which is both the root and a leaf. `

Example 3:

` Input: 1 / 2 / 3

Output: ["1->2->3"]

Explanation: Only one path exists in this left-skewed tree. `