LeetCode || Path Sum II

Path Sum II

耗时：16ms

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]
]

/**
* 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 curr = 0;
bool flag = false;
vector<vector<int>> v;
vector<int> cv;
void dfs(TreeNode* root, int sum)
{
if(curr == sum && root->left == NULL && root->right == NULL)
{
flag = true;
v.push_back(cv);
return;
}

if(root->left!=NULL)
{
cv.push_back(root->left->val);
curr+=root->left->val;
dfs(root->left, sum);
curr-=root->left->val;
cv.pop_back();
}
if(root->right!=NULL)
{
cv.push_back(root->right->val);
curr+=root->right->val;
dfs(root->right, sum);
curr-=root->right->val;
cv.pop_back();
}
}

vector<vector<int>> pathSum(TreeNode* root, int sum) {
if(root == NULL)
return v;

curr+=root->val;
cv.push_back(root->val);
dfs(root, sum);
return v;
}
};