LeetCode-Easy刷题(19) Same Tree

Posted 2022-05-31 当以乐

Given two binary trees, write a function to check if they are the same or not.

Two binary trees are considered the same if they are structurally identical and the nodes have the same value.

Example 1:

Input:     1         1
          / \\       / \\
         2   3     2   3

        [1,2,3],   [1,2,3]

Output: true

Example 2:

Input:     1         1
          /           \\
         2             2

        [1,2],     [1,null,2]

Output: false

Example 3:

Input:     1         1
          / \\       / \\
         2   1     1   2

        [1,2,1],   [1,1,2]

Output: false

判断两个树是否相同,结构和数值都相同则为相同的树

  //树的遍历 结束条件
    public boolean isSameTree(TreeNode p, TreeNode q) 

        if(p==null && q ==null)
            return true;
        

        if(p ==null || q ==null)
            return false;
        

        if(p.val != q.val)
            return false;
        

        return isSameTree(p.left, q.left) && isSameTree(p.right, q.right);
    

class TreeNode 
    int val;
    TreeNode left;
    TreeNode right;
    TreeNode(int x)  val = x;