I just started with Codechef and submitted a few problems.
However I see that there is a special requirement from code by codechef!
For example, my code (http://www.codechef.com/viewsolution/4549459) is running successfully everywhere but getiing a “wrong answer” on codechef.
Why does the output does not match the expected output? Maybe I can be more careful in future before submitting!
Your code is right at sample test-case. but when you are submitting a code then codechef tester check your program in many test-case. So, Carefully read a question and make a program.