leetcode 113.路径总和II

 

 

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这题很简单

/**
 * 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:
vector<int> a;
vector<vector<int>> res;
int l=0;
int summ;
void dfs(TreeNode* r){
    if(r==NULL) return;
    a.push_back(r->val);
    l+=r->val;
    vector<int>b=a;
    int ll=l;
    if(r->left==NULL&&r->right==NULL){
        if(l==summ){
            res.push_back(a);
            return;
        }
        return;
    }
    dfs(r->left);
    a=b;
    l=ll;
    dfs(r->right);
        a=b;
    l=ll;
}
    vector<vector<int>> pathSum(TreeNode* root, int sum) {
        summ=sum;
        dfs(root);
        return res;
    }
};