As we all know codechef does not allow anyone to see testcases because they think it will spoil the fun of thinking extra bit. but i think that even after trying 2-3 hour if one is stuck and does not know where it is going wrong one should see the testcase because though editorial are avaible but for practice one need to know why his/her code is not working or where it is going wrong. because of testcases many people do not practice on codechef.