leetcode:Binary Tree Postorder Traversal

class Solution {public:vector<int> postorderTraversal(TreeNode *root) {vector<int> res;stack<pair<TreeNode *,int>>s;TreeNode *p = root;while(p!=NULL||!s.empty()){while(p){s.push(pair<TreeNode*,int>(p,1));p = p->left;}pair<TreeNode*,int> q = s.top();s.pop();if(q.second==1){s.push(pair<TreeNode*,int>(q.first,2));p = q.first->right;}else{res.push_back(q.first->val);p = NULL;}}return res;}};

，呼唤你前往另一个地方，过上另一种生活。