Same-Tree.java

/**
 * Definition for a binary tree node.
 * public class TreeNode {
 *     int val;
 *     TreeNode left;
 *     TreeNode right;
 *     TreeNode() {}
 *     TreeNode(int val) { this.val = val; }
 *     TreeNode(int val, TreeNode left, TreeNode right) {
 *         this.val = val;
 *         this.left = left;
 *         this.right = right;
 *     }
 * }
 */


class Solution {
	public boolean isSameTree(TreeNode p, TreeNode q) {
		if (p == null && q == null) {
			return true;
		}
		else if (p == null) {
			return false;
		}
		else if (q == null) {
			return false;
		}
		else {
			if (p.val != q.val) {
				return false;
			}
			else {
				boolean left = isSameTree(p.left, q.left);
				boolean right = isSameTree(p.right, q.right);

				return left && right;
			}
		}
	}
}