Leetcode-113. Path Sum II

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] ] 找出二叉树中所有和为sum的路径

思路

深度遍历

代码

class Solution { public: vector<vector<int> > ret; void help(TreeNode *root, vector<int> cur, int target) { cur.push_back(root->val); if(!root->left && !root->right) { if(root->val == target) ret.push_back(cur); return; } if(root->left) help(root->left, cur, target-root->val); if(root->right) help(root->right, cur, target-root->val); } vector<vector<int> > pathSum(TreeNode* root, int sum) { if(!root) return ret; vector<int> temp; help(root, temp, sum); return ret; } };