/**
 * struct TreeNode {
 *  int val;
 *  struct TreeNode *left;
 *  struct TreeNode *right;
 *  TreeNode(int x) : val(x), left(nullptr), right(nullptr) {}
 * };
 */
#include <vector>
class Solution {
  public:
    /**
     * 代码中的类名、方法名、参数名已经指定，请勿修改，直接返回方法规定的值即可
     *
     *
     * @param preOrder int整型vector
     * @param vinOrder int整型vector
     * @return TreeNode类
     */
    TreeNode* reConstructBinaryTree(vector<int>& preOrder, vector<int>& vinOrder) {
        // write code here
        int n = preOrder.size();

        if (!n) {
            return nullptr;
        } else if (n == 1) {
            return new TreeNode(preOrder[0]);
        }

        auto root = new TreeNode( preOrder[0]);
        for (int i = 0; i < vinOrder.size(); i++) {
            if (preOrder[0] == vinOrder[i]) {
                std::vector<int> leftPreOrder(preOrder.begin() + 1, preOrder.begin() + i + 1);
                std::vector<int> leftVInOrder(vinOrder.begin(), vinOrder.begin() + i);
                root->left = reConstructBinaryTree(leftPreOrder, leftVInOrder);

                std::vector<int> rightPreOrder(preOrder.begin() + i + 1, preOrder.end());
                std::vector<int> rightVInOrder(vinOrder.begin() + i + 1, vinOrder.end());
                root->right = reConstructBinaryTree(rightPreOrder, rightVInOrder);
                break;
            }
        }
        return root;
    }
};