Same Tree

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

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

Solution:

  1. /**
  2.  * Definition for a binary tree node.
  3.  * public class TreeNode {
  4.  *     int val;
  5.  *     TreeNode left;
  6.  *     TreeNode right;
  7.  *     TreeNode(int x) { val = x; }
  8.  * }
  9.  */
  10. public class Solution {
  11.   public boolean isSameTree(TreeNode p, TreeNode q) {
  12.     if (p == null && q == null) {
  13.       return true;
  14.     }
  16.     if (p == null || q == null) {
  17.       return false;
  18.     }
  20.     if (p.val != q.val) {
  21.       return false;
  22.     }
  24.     return isSameTree(p.left, q.left) && isSameTree(p.right, q.right);
  25.   }
  26. }