포럼
문제 COCI00648

Logaritam

설명

Hrvoje has recently learned about the logarithm function. He really likes the
property log(\(xy\)) = log(\(x\)) + log(\(y\)), for each pair of positive real numbers \(x\) and \(y\).
He is actually not interested in the function itself, but in logarithmic sequences.
A logarithmic sequence of length \(n\) is a sequence of real numbers (\(a_{1}\), \(a_{2}\), . . . , \(a_{n}\))
for which \(a_{xy} = a_{x} + a_{y}\) holds for every pair of positive integers \(x\) and \(y\) such that
\(xy \le n\). An example of a logarithmic sequence of length 6 is 0, 1, π, 2, 0.7, 1 + π.
For his homework, Hrvoje needed to write \(q\) logarithmic sequences of length \(n\),
however, after a long night of effort he woke up just to find out that Matej had changed exactly one
element of each sequence. Hrvoje doesn’t have a lot of time to correct his homework, so he is interested in
the least number of elements of each sequence he needs to change so the sequence becomes logarithmic
again. Unfortunately, Matej had written his element with a pen, so Hrvoje cannot change that element
of the sequence.
Hrvoje has forgotten which sequences he wrote for his homework so the only thing he knows is the number
of sequences \(q\), the length of each sequence \(n\) and the position \(x_{i}\) of the element Matej had changed in the
\(i\)-th sequence.
Note: It can be proven that for any starting logarithmic sequence the minimal number of changes is the
same.

제약
입력 형식

In the first line there are two positive integers \(n\) and \(q\) (\(1 \le n \le 10^{8}\), \(1 \le q \le 10^{4}\)), the length of each
sequence and the number of sequences.
In the \(i\)-th of the next \(q\) lines there is a positive integer \(x_{i}\) (\(1 \le x_{i} \le n\)), the index of the element Matej
had changed in the \(i\)-th sequence.

출력 형식

In the \(i\)-th line output -1 if Hrvoje cannot change the other elements of the \(i\)-th sequence such that the
sequence becomes logarithmic again, otherwise output the minimal number of changes needed to make
the sequence logarithmic again.

서브태스크
서브태스크점수설명

1

19점

\(n \le 20\), \(q \le 20\)

2

26점

\(q \le 8\)

3

29점

\(n \le 10^{4}\)

4

36점

No additional constraints.

예제 1
입력
6 6
1
2
3
4
5
6
출력
-1
2
1
2
0
1
예제 2
입력
20 5
7
8
2
19
12
출력
1
9
9
0
5
예제 3
입력
10000 4
1234
2345
3456
7890
출력
15
148
3332
37
설명

Clarification of the first example:
If the starting sequence was 0, 1, π, 2, 0.7, 1 + π and Matej changes the fourth element to 8, Hrvoje can
change the second element to 4 and the sixth to 4 + π, after which the sequence 0, 4, π, 8, 0.7, 4 + π will be
logarithmic again.

문제 정보

생성자가 기록되지 않았습니다.

출처 COCI 2022/2023 Contest 5

평가 및 의견

Logaritam

개요
출제자 난이도 Unrated 레이팅 미적용 의견 0 / 1 공개 집계 (커뮤니티 난이도, 주요 주제, 품질)는 의견이 충분히 모이면 공개됩니다.

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Logaritam

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공개
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