Binary Tree Level Order Traversal II
/** * Definition for binary tree * 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) { // Start typing your C/C++ solution below // DO NOT write int main() function stack<vector<int> > mystack; deque<TreeNode *> queue; deque<TreeNode *> prequeue; if(root!=NULL) queue.push_back(root); vector<vector<int> > result; vector<int> temp; while(queue.size()) { temp.clear(); prequeue = queue; queue.clear(); for(deque<TreeNode *>::iterator iter = prequeue.begin();iter!=prequeue.end();iter++) { temp.push_back((*iter)->val); if((*iter)->left!=NULL) queue.push_back((*iter)->left); if((*iter)->right!=NULL) queue.push_back((*iter)->right); } mystack.push(temp); } while(!mystack.empty()) { result.push_back(mystack.top()); mystack.pop(); } return result; } };