112. Path Sum

Problem:

思路：

Solution (C++):

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

性能：

Runtime: 8 ms  Memory Usage: 19.9 MB