[原创]leet code - path 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) {
        // Start typing your C/C++ solution below
        // DO NOT write int main() function
        if(root)
        {
            if(root->val == sum && root->left == NULL && root->right == NULL)
                return 1;
            else if(root->left && !root->right)
            {
                root->left->val +=root->val;
                return hasPathSum(root->left,sum);
            }
            else if(root->right && !root->left)
            {
                root->right->val += root->val;
                return hasPathSum(root->right,sum);
            }
            else if(root->left && root->right)
            {
                root->left->val += root->val;
                root->right->val += root->val;
                return (hasPathSum(root->right,sum)||hasPathSum(root->left,sum));
            }
            else if(root->left == NULL && root->right == NULL)
            {
                if(root->val == sum)
                    return 1;
                else return 0;
                
            }
        }
        else return 0;
        
    }
};