112

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

Companies:
Facebook, Amazon, Microsoft, ByteDance

Related Topics:
Tree, Depth-first Search

Similar Questions:

• Path Sum II (Medium)
• Binary Tree Maximum Path Sum (Hard)
• Sum Root to Leaf Numbers (Medium)
• Path Sum III (Medium)
• Path Sum IV (Medium)

Solution 1.

// OJ: https://leetcode.com/problems/path-sum/
// Author: github.com/lzl124631x
// Time: O(N)
// Space: O(H)
class Solution {
public:
    bool hasPathSum(TreeNode* root, int target) {
        if (!root) return false;
        if (!root->left && !root->right) return target == root->val;
        return hasPathSum(root->left, target - root->val) || hasPathSum(root->right, target - root->val);
    }
};