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.

/**
 * Definition for binary tree
 * public class TreeNode {
 *     int val;
 *     TreeNode left;
 *     TreeNode right;
 *     TreeNode(int x) { val = x; }
 * }
 */
public class Solution {
    public boolean isSameTree(TreeNode p, TreeNode q) {
         if (p==null&&q==null) {
            return true;
        } else if (p==null) {
            return q==null;
        } else if (q==null){
            return p==null;
        }
         return (p.val==q.val)&&isSameTree(p.left,q.left)&&isSameTree(p.right,q.right);    
    }
}