[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;

}
};