10181018 SUSTech Online Judge
Problem 1018 --Cut Ropes for Lily

1018: Cut Ropes for Lily

Time Limit: 2 Sec  Memory Limit: 128 MB
Submit: 830  Solved: 61
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Lily asked Huang Bo: “We have n ropes at hand, and we want to cut them into some pieces. And we also want to get at least k ropes with the same length. Can you give me the answer of the longest length of these k ropes?” Huang Bo thought for a while and said that we can sort the ropes by their length in descending order, and the kth biggest length is the answer. Lily said: “No, you are wrong”. Lily is unhappy with Huang Bo’s answer, and Huang Bo is in trouble, can you help him?


There are multiple test cases(less than 1000), for each test case, the first line will be two integers n and k( 0 <= n <= 1000, 0 < k <= 10000), the second line will be n floating numbers and the ith number is the length of i-th ropes, noted as ai (0<= ai <= 100000). And all lengths in the input file are written with a centimeter precision, with exactly two digits after a decimal point.


One floating number the longest length of these k ropes for each test case. Please notice that the number must be written with exactly two digits after decimal point.

Sample Input

4 8
2.00 2.00 2.00 2.00
4 8
1.71 2.32 6.33 8.00

Sample Output



Bonus problem. Binary search. Try to avoid doing binary search in floating numbers and pay attention to 0.