题解 | #重建二叉树#

import java.util.*;

/*
 * public class TreeNode {
 *   int val = 0;
 *   TreeNode left = null;
 *   TreeNode right = null;
 *   public TreeNode(int val) {
 *     this.val = val;
 *   }
 * }
 */

public class Solution {
    /**
     * 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整型一维数组
     * @param vinOrder int整型一维数组
     * @return TreeNode类
     */
    public TreeNode reConstructBinaryTree(int [] preOrder, int [] vinOrder) {
        if (preOrder.length == 0 && vinOrder.length == 0) return null;
        TreeNode node = new TreeNode(preOrder[0]);
        for (int i = 0; i < vinOrder.length; i++) {
            if (vinOrder[i] == preOrder[0]) {
                node.left = reConstructBinaryTree(Arrays.copyOfRange(preOrder, 1, i + 1),
                                                  Arrays.copyOfRange(vinOrder, 0, i));
                node.right = reConstructBinaryTree(Arrays.copyOfRange(preOrder, i + 1,
                                                   preOrder.length), Arrays.copyOfRange(vinOrder, i + 1, vinOrder.length));
            }
        }
        return node;

    }

}