LeetCode in TypeScript
112. Path Sum
Easy
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.
Example 1:
Input: root = [5,4,8,11,null,13,4,7,2,null,null,null,1], targetSum = 22
Output: true
Example 2:
Input: root = [1,2,3], targetSum = 5
Output: false
Example 3:
Input: root = [1,2], 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
Solution
import { TreeNode } from '../../com_github_leetcode/treenode'
/**
* Definition for a binary tree node.
* class TreeNode {
* val: number
* left: TreeNode | null
* right: TreeNode | null
* constructor(val?: number, left?: TreeNode | null, right?: TreeNode | null) {
* this.val = (val===undefined ? 0 : val)
* this.left = (left===undefined ? null : left)
* this.right = (right===undefined ? null : right)
* }
* }
*/
function hasPathSum(root: TreeNode | null, targetSum: number): boolean {
if (root === null) {
return false
}
if (targetSum === root.val && root.left === null && root.right === null) {
return true
}
return hasPathSum(root.left, targetSum - root.val) || hasPathSum(root.right, targetSum - root.val)
}
export { hasPathSum }