LeetCode-113-Path Sum II

发布时间：2020-12-14 04:26:09 所属栏目：大数据来源：网络整理

导读：算法描述： Given a binary tree and a sum,find all root-to-leaf paths where each path‘s sum equals the given sum. Note:?A leaf is a node with no children. Example: Given the below binary tree and? sum = 22 , 5 / 4 8 / / 11 13 4 / / 7 2 5

算法描述：

Given a binary tree and a sum,find all root-to-leaf paths where each path‘s sum equals the given sum.

Note:?A leaf is a node with no children.

Example:

Given the below binary tree and?sum = 22,

      5
     /     4   8
   /   /   11  13  4
 /      / 7    2  5   1

Return:

[
   [5,4,11,2],[5,8,5]
]

解题思路：回溯法。注意确认边界条件。

    vector<vector<int>> pathSum(TreeNode* root,int sum) {
        vector<vector<int>> results;
        vector<int> temp;
        backtracking(root,results,temp,sum);
        return results;
    }
    
    void backtracking(TreeNode* root,vector<vector<int>>& results,vector<int>& temp,int sum){
        if(root==nullptr) return;
        temp.push_back(root->val);
        if(sum ==root->val && root->left==nullptr && root->right==nullptr){
            results.push_back(temp);
        } 
        backtracking(root->left,sum-root->val);
        backtracking(root->right,sum-root->val);
        temp.pop_back();
    }

（编辑：李大同）

【声明】本站内容均来自网络，其相关言论仅代表作者个人观点，不代表本站立场。若无意侵犯到您的权利，请及时与联系站长删除相关内容!