Sliding Window Summation
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Bessie has a hidden binary string \(b_1b_2\dots b_N\) (\(1\le N\le 2\cdot 10^5\)).
The only information about \(b\) you are given is a binary string
\(r_1r_2\dots r_{N-K+1}\) (\(1 \le K \le N\)), where \(r_i\) is the remainder when
the number of ones in the length-\(K\) window of \(b\) with leftmost index \(i\) is
divided by two.
Output the minimum and maximum possible numbers of ones in Bessie's hidden
binary string.
Problem credits: Benjamin Qi
SCORING
- Input 2: \(N\le 8\)
- Inputs 3-4: \(K\le 8\) and the sum of \(N\) over all tests does not exceed \(10^4\).
- Inputs 5-11: No additional constraints.
Problem credits: Benjamin Qi
There are \(T\) (\(1\le T\le 10^3\)) independent test cases to be solved. Each test
is specified by the following:
The first line contains \(N\) and \(K\).
The second line contains the binary string \(r_1\dots r_{N-K+1}\), where
\(r_i=\sum_{j=i}^{j+K-1}b_j\pmod{2}\).
It is guaranteed that the sum of \(N\) over all tests does not exceed \(10^6\).
For each test case, output the minimum and maximum possible numbers of ones in
Bessie's hidden binary string, separated by a single space.
7
5 1
10011
5 2
1001
5 3
100
5 5
0
5 5
1
4 4
1
5 2
00003 3
2 3
1 4
0 4
1 5
1 3
0 5For the first test case, \(K=1\) means that \(r=b\), and the number of ones in \(r\)
is \(3\).
For the second test case, there are two possibilities for \(b\): 10001 and 01110,
having \(2\) and \(3\) ones, respectively.
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Sliding Window Summation