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.

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