LeetCode 107. Binary Tree Level Order Traversal II
Solution1：我的答案
比102那道题多了一行代码。。。
/** * 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<vector<int>> levelOrderBottom(TreeNode* root) { vector<vector<int> > res; if (!root) return res; vector<int> temp; queue<TreeNode* > my_que; //队列用来暂时存储二叉树节点 my_que.push(root); int cur = 1, next = 0; while (!my_que.empty()) { temp.push_back(my_que.front()->val); cur--; if (my_que.front()->left) { my_que.push(my_que.front()->left); next++; } if (my_que.front()->right) { my_que.push(my_que.front()->right); next++; } my_que.pop(); if (cur == 0) { res.push_back(temp); temp.clear(); cur = next; next = 0; } } reverse(res.begin(), res.end()); return res; } };