题目描述
输入某二叉树的前序遍历和中序遍历的结果，请重建出该二叉树。假设输入的前序遍历和中序遍历的结果中都不含重复的数字。例如输入前序遍历序列{1,2,4,7,3,5,6,8}和中序遍历序列{4,7,2,1,5,3,8,6}，则重建二叉树并返回。
解题思路
代码实现
import java.util.Arrays;
class TreeNode {
int val;
TreeNode left;
TreeNode right;
TreeNode(int x) { val = x; }
}
public class Solution {
public TreeNode reConstructBinaryTree(int [] pre,int [] in) {
if (pre.length == 0) {
return null;
}
TreeNode node = null;
for (int i = 0; i < in.length; i++) {
if (pre[0] == in[i]) {
node = new TreeNode(pre[0]);
node.left = reConstructBinaryTree(
Arrays.copyOfRange(pre, 1, i+1),Arrays.copyOfRange(in, 0, i));
node.right = reConstructBinaryTree(
Arrays.copyOfRange(pre, i + 1, pre.length),
Arrays.copyOfRange(in, i + 1, in.length));
}
}
return node;
}}
