Leetcoede 112 Path Sum 二叉树

二叉树的从叶子到根的和是否存在

/**
 * Definition for binary tree
 * struct TreeNode {
 *     int val;
 *     TreeNode *left;
 *     TreeNode *right;
 *     TreeNode(int x) : val(x), left(NULL), right(NULL) {}
 * };
 */
class Solution {
public:

bool hasPathSum(TreeNode *root, int sum) {
    if (!root)
    {
        return false;
    }
    if (!root->left && !root->right)
    {
        return sum == root->val;
    }
    return hasPathSum(root->left,sum - root->val)||hasPathSum(root->right,sum - root->val);
}