Facebook Hacker Cup : “Studious Student” Solution in Java

This program is a solution to Studious Student problem from Facebook Hacker Cup. The problem can be found here: link.

The problem:

Studious Student

You’ve been given a list of words to study and memorize. Being a diligent student of language and the arts, you’ve decided to not study them at all and instead make up pointless games based on them. One game you’ve come up with is to see how you can concatenate the words to generate the lexicographically lowest possible string.

Input

As input for playing this game you will receive a text file containing an integer N, the number of word sets you need to play your game against. This will be followed by N word sets, each starting with an integer M, the number of words in the set, followed by M words. All tokens in the input will be separated by some whitespace and, aside from N and M, will consist entirely of lowercase letters.

Output

Your submission should contain the lexicographically shortest strings for each corresponding word set, one per line and in order.

Constraints

1 <= N <= 100
1 <= M <= 9
1 <= all word lengths <= 10

Example input

5
6 facebook hacker cup for studious students
5 k duz q rc lvraw
5 mybea zdr yubx xe dyroiy
5 jibw ji jp bw jibw
5 uiuy hopji li j dcyi

Example output

cupfacebookforhackerstudentsstudious
duzklvrawqrc
dyroiymybeaxeyubxzdr
bwjibwjibwjijp
dcyihopjijliuiuy

Output:
Output for Studious Student

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  • jac

    hello,

    what about such an input:

    1
    2 ab abb

    your program gives abbab, shouldn’t it be ababb instead ?

    • Vlad

      Hi jac, I have made certain changes to the code (line 28). The program gives expected results for all the cases, including the case which you mentioned.

  • Vlad

    You are right, i will have to take a look into the code for that particular case. Thanks for the heads up.