Same Tree

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(null == p && null == q)
            return true;
        if(null == p || null == q)
            return false;
        else{
            return p.val == q.val && isSameTree(p.left, q.left) && isSameTree(p.right, q.right);
        }
    }
}