1 /* 2 * @lc app=leetcode.cn id=107 lang=cpp 3 * 4 * [107] 二叉树的层次遍历 II 5 */ 6 7 // @lc code=start 8 /** 9 * Definition for a binary tree node. 10 * struct TreeNode { 11 * int val; 12 * TreeNode *left; 13 * TreeNode *right; 14 * TreeNode(int x) : val(x), left(NULL), right(NULL) {} 15 * }; 16 */ 17 class Solution { 18 public: 19 //和102一样的思路，最后加一个翻转 20 vector<vector<int>> levelOrderBottom(TreeNode* root) { 21 if(!root) return {}; 22 vector<vector<int>> res; 23 queue<TreeNode*> q; 24 25 q.push(root); 26 while(!q.empty()){ 27 int len=q.size(); 28 vector<int> tmp; 29 for(int i=0;i<len;i++){ 30 TreeNode* node=q.front(); 31 q.pop(); 32 tmp.push_back(node->val); 33 if(node->left) q.push(node->left); 34 if(node->right) q.push(node->right); 35 } 36 res.push_back(tmp); 37 38 } 39 reverse(res.begin(),res.end()); 40 return res; 41 } 42 }; 43 // @lc code=end