[leetcode]113. Path Sum II (medium)

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]
]

解题思路：

同path sum思路差不多，不过区别是这次要记录sum=given sum时的路径。

所以在每次dfs时用一个vector保存各个path的路径就可以了。

代码

class Solution {
public:
vector<vector<int>> m;

void dfs(TreeNode* root,int s,int c,vector<int> v)
{

c=c+root->val;
v.push_back(root->val);
if(root->left==NULL&&root->right==NULL)
{
if(c==s)
{
// cout<<c<<endl;
m.push_back(v);


}




}
if(root->left)
dfs(root->left,s,c,v);
if(root->right)
dfs(root->right,s,c,v);


// return dfs(root->right,s,c);

}
vector<vector<int>> pathSum(TreeNode* root, int sum) {
if(!root)
return m;
vector<int> v;
dfs(root,sum,0,v);
return m;
}
};