【LeetCode 36】113.路径总和II

class Solution {
public:
    vector<vector<int>> result;
    vector<int> path;
    //递归不需要返回值，因为我们要遍历整个树
    void traversal(TreeNode *cur,int count)
    {
        //遇到了叶子节点，并且找到了he为sum的路径
        if(!cur->left&&!cur->right&&count==0)
        {
            result.push_back(path);
            return;
        }
        if(!cur->left&&!cur->right) return;//遇到叶子节点而没有找到合适的边，直接返回
        if(cur->left)//左
        {
            path.push_back(cur->left->val);
            count-=cur->left->val;
            traversal(cur->left,count);//递归
            count+=cur->left->val;//回溯
            path.pop_back();//回溯
        }
        if(cur->right)
        {
            path.push_back(cur->right->val);
            count-=cur->right->val;
            traversal(cur->right,count);//递归
            count+=cur->right->val;//回溯
            path.pop_back();//回溯
        }
        return ;
    }
    vector<vector<int>> pathSum(TreeNode* root, int targetSum) {
        result.clear();
        path.clear();
        if(root==NULL) return result;
        path.push_back(root->val);//把根节点放进路径
        traversal(root,targetSum-root->val);
        return result;
    }
};
,targetSum-root->val);
        return result;
    }
};