# 30. 相同的树

java

```java
// 链表工具类
public class LinkedUtils {
    public static ListNode arrayToLinkedList(int[] array){
        if(array==null) return null;
        //head node 
        ListNode root=new ListNode(-1);
        ListNode p=root;

        int size=array.length;
        int i=0;
        while(i<size){
            ListNode q=new ListNode(array[i++]);
            q.next=null;
            p.next=q;
            p=q;
        }

        return root.next;
    }

    public static void print(ListNode root) {
        if(root==null) System.out.println("root is null");
        else{
            while(root!=null){
                System.out.print(root.val);
                if(root.next!=null){
                    System.out.print("->");
                }
                root=root.next;
            }
            System.out.println();
        }
    }

    public static int length(ListNode root) {
        if(root==null) return 0;
        int n=0;
        while(root!=null){
            root=root.next;
            n++;
        }
        return n;
    }

    // 返回指向链表尾部的指针
    public static ListNode moveToTail(ListNode root) {
        if(root==null) return null;
        ListNode tail=root;
        while(tail.next!=null){
            tail=tail.next;
        }
        return tail;
    }
}


// 定义链表
public class ListNode {
    public int val;
    public ListNode next;

    public ListNode(int val) {
        this.val=val;
    }
}


/**
 * 100. 相同的树
 * 给定两个二叉树，编写一个函数来检验它们是否相同。
 *
 * 如果两个树在结构上相同，并且节点具有相同的值，则认为它们是相同的。
 *
 * 示例 1:
 *
 * 输入:       1         1
 *           / \       / \
 *          2   3     2   3
 *
 *         [1,2,3],   [1,2,3]
 *
 * 输出: true
 *
 * 示例 2:
 *
 * 输入:      1          1
 *           /           \
 *          2             2
 *
 *         [1,2],     [1,null,2]
 *
 * 输出: false
 *
 * 示例 3:
 *
 * 输入:       1         1
 *           / \       / \
 *          2   1     1   2
 *
 *         [1,2,1],   [1,1,2]
 *
 * 输出: false
 */
public class Solution100 {
    public boolean isSameTree(TreeNode p, TreeNode q) {
        //p,q不一致
        if(p==null&&q!=null) return false;
        if(p!=null&&q==null) return false;

        //判断左子树、右子树
        if(p!=null&&q!=null){
            if(!isSameTree(p.left,q.left)||!isSameTree(p.right,q.right)) return false;
            if(p.val!=q.val) return false;
        }
        return true;
    }

    public static void main(String[] args) {
        String pstr="12##4##";
        String qstr="12##3##";
        TreeNode p=TreeUtils.stringToTree(pstr);
        TreeNode q=TreeUtils.stringToTree(qstr);
        boolean b = new Solution100().isSameTree(p, q);
        System.out.println(b);
    }
}
```

python

```
```


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