LeetCode Path Sum II

题目

Given a binary tree and a sum, find all root-to-leaf paths where each path's sum equals the given sum. For example:

Given the below binary tree and

sum = 22

,

5
/ \
4   8
/   / \
11  13  4
/  \    / \
7    2  5   1

return

[
[5,4,11,2],
[5,8,4,5]
]

与上一题相似，保存当前的探测路径，符合要求时存入即可。

代码

/**
* Definition for binary tree
* struct TreeNode {
*     int val;
*     TreeNode *left;
*     TreeNode *right;
*     TreeNode(int x) : val(x), left(NULL), right(NULL) {}
* };
*/
class Solution {
vector<vector<int>> ret;	//返回值
vector<int> stack;	//记录路线堆栈
public:
void innerPathSum(TreeNode *root,int sum)	//内部递归求解
{
if(root==NULL)
return;
stack.push_back(root->val);	//压入当前值
if(root->val==sum&&root->left==NULL&&root->right==NULL)
ret.push_back(stack);
innerPathSum(root->left,sum-root->val);	//递归
innerPathSum(root->right,sum-root->val);
stack.pop_back();	//弹出当前值
}
vector<vector<int> > pathSum(TreeNode *root, int sum) {
ret.clear();
stack.clear();
innerPathSum(root,sum);
return ret;
}
};