文章作者：Tyan
博客：noahsnail.com | CSDN | 简书
1. Description
Path Sum III
2. Solution
- Recursive
/**
* Definition for a binary tree node.
* struct TreeNode {
* int val;
* TreeNode *left;
* TreeNode *right;
* TreeNode(int x) : val(x), left(NULL), right(NULL) {}
* };
*/
class Solution {
public:
int pathSum(TreeNode* root, int sum) {
if(!root) {
return 0;
}
int paths = 0;
path(root, sum, paths);
return paths + pathSum(root->left, sum) + pathSum(root->right, sum);
}
void path(TreeNode* root, int sum, int& paths) {
if(root->val == sum) {
paths++;
}
if(root->left) {
path(root->left, sum - root->val, paths);
}
if(root->right) {
path(root->right, sum - root->val, paths);
}
}
};
