100 Same Tree

Problem

100 Same Tree

Solution

This problem is a great example for recursion, two binary trees are same if and only if they have:

• same root node
• same left subtree
• same right subtree

To get the answer, just perform above check recursively for every trees and subtrees.

Code

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