Path Sum II

/**
 * Definition for binary tree
 * struct TreeNode {
 *     int val;
 *     TreeNode *left;
 *     TreeNode *right;
 *     TreeNode(int x) : val(x), left(NULL), right(NULL) {}
 * };
 */
class Solution {
public:
    vector<vector<int> >res;//记录结果
    void dfs(TreeNode *root,int sum,vector<int> temp){//temp记录每一条可能的路径
        if(!root) return;
        if(!root->left&&!root->right&&sum == root->val){//满足条件
            temp.push_back(sum);
            res.push_back(temp);
        }
        temp.push_back(root->val);
        dfs(root->left,sum-root->val,temp);
        dfs(root->right,sum-root->val,temp);
    }
    vector<vector<int> > pathSum(TreeNode *root, int sum) {
        vector<int>temp;
        dfs(root,sum,temp);
        return res;
    }
};