INS14C  Digo plays with Numbers
Digo and his friend Sharry have completed their missions and were relaxing. Both of them love mathematics and love to play with numbers. They have a book in which several binary strings are written. Digo comes up with an idea of an interesting game. He asks Sharry to think of a number K, which is less than or equal to the length of the string N. Both players play alternately. In his turn, a person can remove any bit from the binary string. Digo removes such as to maximize the value of the leftover binary string while Sharry plays to minimze the string. This process continues till K binary digits are left. You have to tell those K binary digits left after the game is over.
It is given that Sharry always plays first.
Input Format:
The first line consists of a single integer T, denoting the number of test cases.
2*T lines follow. For every test case, the first line consists of two integers N and K, denoting the initial length of the string and its length at the end of the game. The second line for the test case contains the initial binary string of length N.
Output Format:
For each test case print the final string left after removal of characters.
Constraints:
1 <= T <= 1000
1 <= N <= 1000
1 <= K <= N
Sample Input:
2
5 3
10010
4 2
1111
Sample Output:
010
11
hide comments
nadstratosfer:
20170926 06:45:49
dwij28: Just got AC with Python3 at less than half your PyPy time :P. It's exactly this kind of problems where optimizing Python code is fun, because you have to know what you're doing rather than have the compiler figure it out for you. 

dwij28:
20160826 23:02:30
Python 2.7 gets a TLE, PyPy gets an AC. I am too lazy to optimize or write adhoc string problems in C++. 

rayhan50001:
20160617 12:14:32
critical case:


samyak choudhary:
20150624 16:22:26
" a person CAN remove any bit", wrongly worded question  that "can" should not be there, it costed me 2 wa.


darol:
20150122 22:04:34
found it after few WA, missed that K can be Equal to N so the string printed is same as readed. Last edit: 20150122 22:34:58 

bourne:
20140912 09:51:25
Getting strange "Internal Error" ...any ideas why ? Thanks 

Raghav Aggiwal:
20140904 20:12:27
@surya kiran sir : can u plz tell me where i m going wrong http://ideone.com/fork/UhKKd6


abhishek arora:
20140816 15:32:10
@Surya kiran.. pls help..getting wrong answer..( Submission id 12162332 ) 

Prajval Prabhakar:
20140810 08:39:26
My 50th :) 

drfgthyjuikjhgftrd:
20140609 07:10:49
pls help getting wa:( http://ideone.com/0hts07 
Added by:  Surya Kiran 
Date:  20140320 
Time limit:  1s 
Source limit:  50000B 
Memory limit:  1536MB 
Cluster:  Cube (Intel G860) 
Languages:  All except: ASM64 
Resource:  Insomnia 2014 