leetcode_num112_Path Sum

Given a binary tree and a sum, determine if the tree has a root-to-leaf path such that adding up all the values along the path equals
the given sum.

/**
 * 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==NULL)
            return false;
        int y;
        y=root->val;
        if ((root->left==NULL) and (root->right==NULL)){
            if (y==sum)
                return true;
            else
                return false;
            }
        else{
            int z;
            z=sum-y;
            bool check,check1,check2;
            check1=hasPathSum(root->left,z);
            check2=hasPathSum(root->right,z);
            check= (check1 or check2);
            return check;
        }
    }
};