免费软件下载官方网站,外贸建站是什么意思,做报纸能经常更新网站,媒体网站2023.10.21 本题需要根据前序遍历序列和中序遍历序列来构造出一颗二叉树。类似于从中序与后序遍历序列构造二叉树 。使用递归#xff0c; java代码如下#xff1a;
/*** Definition for a binary tree node.* public class TreeNode {* int val;* TreeNode left;* …2023.10.21 本题需要根据前序遍历序列和中序遍历序列来构造出一颗二叉树。类似于从中序与后序遍历序列构造二叉树 。使用递归 java代码如下
/*** Definition for a binary tree node.* public class TreeNode {* int val;* TreeNode left;* TreeNode right;* TreeNode() {}* TreeNode(int val) { this.val val; }* TreeNode(int val, TreeNode left, TreeNode right) {* this.val val;* this.left left;* this.right right;* }* }*/
class Solution {public TreeNode buildTree(int[] preorder, int[] inorder) {if(inorder.length 0) return null;int rootValue preorder[0];TreeNode root new TreeNode(rootValue);if(inorder.length 1) return root;//找到中序遍历的切割点int seg 0;for(int i0; iinorder.length; i){if(inorder[i] rootValue){seg i;break;}}int[] in_left Arrays.copyOfRange(inorder,0,seg);int[] in_right Arrays.copyOfRange(inorder,seg1,preorder.length);preorder Arrays.copyOfRange(preorder,1,preorder.length);//去掉第一个元素也就是根节点的值int[] pre_left Arrays.copyOfRange(preorder,0,in_left.length);int[] pre_right Arrays.copyOfRange(preorder,in_left.length,preorder.length);//递归处理左右子树root.left buildTree(pre_left,in_left);root.right buildTree(pre_right,in_right);return root;}
}
