题解 | #输出二叉树的右视图#

 * Definition for binary tree
 * struct TreeNode {
 *     int val;
 *     TreeNode *left;
 *     TreeNode *right;
 *     TreeNode(int x) : val(x), left(NULL), right(NULL) {}
 * };
 */
class Solution {
public:
    TreeNode* reConstructBinaryTree(vector<int> pre,vector<int> vin) {
        if(pre.empty()||vin.empty())return NULL;
        TreeNode* root = new TreeNode(pre[0]);
        stack<TreeNode* > tmp;
        tmp.push(root);
        int t=0;
        for(int i=1;i<pre.size();i++){
            TreeNode* node = tmp.top();
            if(node->val!=vin[t]){
                node->left = new TreeNode(pre[i]);
                tmp.push(node->left);
            }
            else{
                while(!tmp.empty()&&tmp.top()->val==vin[t]){
                     node = tmp.top();
                    tmp.pop();
                    t++;
                }
                node->right = new TreeNode(pre[i]);
                tmp.push(node->right);
//                 node->right = new TreeNode(pre[i]);
//                 t++;
//                 tmp.pop();
//                 tmp.push(node->right);
            }
        }
        return root;
         
    }
};