Codeforces Global Round 23 |
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Finished |
You have an array $$$a$$$ of size $$$n$$$ consisting only of zeroes and ones and an integer $$$k$$$. In one operation you can do one of the following:
Determine if it's possible to turn $$$a$$$ into $$$[1]$$$ after several (possibly zero) operations.
Each test contains multiple test cases. The first line contains the number of test cases $$$t$$$ ($$$1 \le t \le 1000$$$). The description of the test cases follows.
The first line of each test case contains two integers $$$n$$$ and $$$k$$$ ($$$2 \le k \le n \le 50$$$), the size of array $$$a$$$ and the length of segments that you can perform second type operation on.
The second line contains $$$n$$$ integers $$$a_{1}, a_{2}, \ldots, a_{n}$$$ ($$$a_i$$$ is $$$0$$$ or $$$1$$$), elements of array $$$a$$$.
For each test case, if it is possible to turn $$$a$$$ into $$$[1]$$$, print "YES", otherwise print "NO".
73 20 1 05 31 0 1 1 02 21 14 40 0 0 06 30 0 1 0 0 17 51 1 1 1 1 1 15 30 0 1 0 0
YES YES YES NO YES YES YES
In the first test case, you can perform the second type operation on second and third elements so $$$a$$$ becomes $$$[0, 1]$$$, then you can perform the second type operation on first and second elements, so $$$a$$$ turns to $$$[1]$$$.
In the fourth test case, it's obvious to see that you can't make any $$$1$$$, no matter what you do.
In the fifth test case, you can first perform a type 2 operation on the first three elements so that $$$a$$$ becomes $$$[1, 0, 0, 1]$$$, then perform a type 2 operation on the elements in positions two through four, so that $$$a$$$ becomes $$$[1, 1]$$$, and finally perform the first type operation on the remaining elements, so that $$$a$$$ becomes $$$[1]$$$.
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