Leetcode-Solutions/112-path-sum.cpp at main · aghersidev/Leetcode-Solutions · GitHub

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/**
 * Definition for a binary tree node.
 * struct TreeNode {
 *     int val;
 *     TreeNode *left;
 *     TreeNode *right;
 *     TreeNode() : val(0), left(nullptr), right(nullptr) {}
 *     TreeNode(int x) : val(x), left(nullptr), right(nullptr) {}
 *     TreeNode(int x, TreeNode *left, TreeNode *right) : val(x), left(left), right(right) {}
 * };
 */
class Solution {
public:
    bool sumNodes(TreeNode* root, int targetSum, int sum) {
        if (!root) {
            return targetSum == sum;
        }
        if (!root->left) return sumNodes(root->right,targetSum,sum + root->val);
        if (!root->right) return sumNodes(root->left,targetSum,sum + root->val);
        return (sumNodes(root->left,targetSum,sum + root->val) && root->left) ||
        (sumNodes(root->right,targetSum,sum + root->val) && root->right);
    }
    bool hasPathSum(TreeNode* root, int targetSum) {
        int sum = 0;
        if (!root) { return false;}
        return sumNodes(root,targetSum,0);
    }
};