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Path Sum

easy

LeetCode 112. Path Sum

Given the root of a binary tree and an integer targetSum, return true if the tree has a root-to-leaf path such that adding up all the values along the path equals targetSum.

A leaf is a node with no children.

Examples

Example 1

Input:  root = [5,4,8,11,null,13,4,7,2,null,null,null,1], targetSum = 22

5 / \ 4 8 / / \ 11 13 4 / \ \ 7 2 1Output: true The path 5 → 4 → 11 → 2 sums to 22.

Example 2

Input:  root = [1,2,3], targetSum = 5
Output: false

Example 3

Input:  root = [], targetSum = 0
Output: false

Constraints

  • The number of nodes in the tree is in the range [0, 5000]
  • -1000 <= Node.val <= 1000
  • -1000 <= targetSum <= 1000

How the tests work: trees are written as level-order arrays — [1,null,2] is a root 1 with a right child 2. Your function receives real TreeNode objects.

TypeScript
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List of test cases (8)
Case 1
root = [5,4,8,11,null,13,4,7,2,null,null,null,1]
targetSum = 22
Case 2
root = [1,2,3]
targetSum = 5
Case 3
root = []
targetSum = 0
Case 4
root = [1,2]
targetSum = 1
Case 5
root = [1,2]
targetSum = 3
Case 6
root = [1]
targetSum = 1
Case 7
root = [1,-2,-3,1,3,-2,null,-1]
targetSum = -1
Case 8
root = [5,4,8,11,null,13,4,7,2,null,null,null,1]
targetSum = 27