题目描述
输入两棵二叉树A,B,判断B是不是A的子结构。(ps:我们约定空树不是任意一个树的子结构)
/**
public class TreeNode {
int val = 0;
TreeNode left = null;
TreeNode right = null;
public TreeNode(int val) {
this.val = val;
}
}
*/
import java.util.LinkedList;
public class Solution {
public boolean HasSubtree(TreeNode root1,TreeNode root2) {
if(root2==null||root1==null) return false;
LinkedList<TreeNode> queue = new LinkedList<>();
queue.add(root1);
while(queue.size()>0) {
TreeNode node = queue.pollFirst();
if(isSubTree(node,root2)) {
return true;
}else{
if(node.left!=null) {
queue.add(node.left);
}
if(node.right!=null) {
queue.add(node.right);
}
}
}
return false;
}
public boolean isSubTree(TreeNode root1,TreeNode root2) {
if(root2==null) return true;
if(root1==null && root2!=null) return false;
if(root1.val==root2.val) {
boolean left = isSubTree(root1.left,root2.left);
boolean right = isSubTree(root1.right,root2.right);
return left&right;
}else{
return false;
}
}
}