100. Same Tree

/**
* Definition for a binary tree node.
* 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;
if(p == null || q== null) return false;

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