题解 | #树的子结构#

隔了几天在lc上看到又是不一样的思路，天天新题，愁得慌

/**
public class TreeNode {
    int val = 0;
    TreeNode left = null;
    TreeNode right = null;

    public TreeNode(int val) {
        this.val = val;

    }

}
*/
import java.util.*;
public class Solution {
    public boolean HasSubtree(TreeNode root1,TreeNode root2) {
        TreeNode A = root1;
        TreeNode B = root2;
        if(B == null || A == null){
            return false;
        }
        Queue<TreeNode> queue = new LinkedList<>();
        Queue<TreeNode> queueB = new LinkedList<>();
        Queue<TreeNode> queueA = new LinkedList<>();
        TreeNode op;
        TreeNode opA;
        TreeNode opB = B;
        queue.offer(A);
        while(true){
            op = queue.poll();
    
             if(op.left != null ){
                 queue.offer(op.left);
             }
             if(op.right != null){
                 queue.offer(op.right);
             }
             opA = op;
             queueA.offer(opA);
             queueB.offer(B);
             while(true){
                 opA = queueA.poll();
                 opB = queueB.poll();
                if(opA.val != opB.val){
                     break;
                }
                if(opA.left == null && opB.left != null){
                    break;
                }
                
                 
                 if(opA.right == null && opB.right != null){
                         break;
                 }
                if(opA.left != null && opB.left != null){
                    queueA.offer(opA.left);
                    queueB.offer(opB.left);
                }
                if(opA.right != null && opB.right != null){
                    queueA.offer(opA.right);
                    queueB.offer(opB.right);
                }
                
              
                if(queueA.isEmpty() &&  !queueB.isEmpty()){
                    return false;
                }
                else if(!queueA.isEmpty() && queueB.isEmpty()){
                    return true;
                }
                else if(queueA.isEmpty() && queueB.isEmpty()){
                    return true;
                }

            }
            queueA.clear();
            queueB.clear();
            if(queue.isEmpty()){
                break;
            }
             
        }
        return false;


    }
}