Same_Tree.cpp

/*
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
 * struct TreeNode {
 *     int val;
 *     TreeNode *left;
 *     TreeNode *right;
 *     TreeNode(int x) : val(x), left(NULL), right(NULL) {}
 * };
 */

class Solution {
public:
    bool isSameTree(TreeNode *p, TreeNode *q) {
        if (p == NULL && q == NULL)
            return true;
        else if (p != NULL && q == NULL)
            return false;
        else if (p == NULL && q != NULL)
            return false;
        else {
            bool result = isSameTree(p->left, q->left);
            if (!result)
                return false;
            if (p->val != q->val) {
                return false;
            }
            return isSameTree(p->right, q->right);
        }
    }
};