No.1394 Changing Problems
タグ : / 解いたユーザー数 9
作問者 :
platinum
Problem Statement
Chinerist, a math teacher, is planning to set the following problem on a test.
[Problem]
There are $N$ integers $A_i\ (1\le i \le N)$.
You may perform the following operation any number of times.
Operation: Choose an integer $k\ (1\le k\le N)$. Then add $N-2$ to $A_k$ and subtract $1$ from every other element.
The values of $A_i$ may become negative through this operation.
You want to make all $A_i\ (1\le i \le N)$ at most $N-2$ by performing the operation $0$ or more times. It can be proved that this can be achieved in a finite number of operations.
Find the minimum number of operations required.
For the initial values of $N,\ A_i$, the teacher has a set prepared when the problem was given on a past test.
However, reusing them as they are would be bad, so the teacher decided to try changing the values of $A_i$ in various ways.
You are given the integer $N$ and the $N$ integers $A_i\ (1\le i \le N)$ prepared by Chinerist.
$Q$ queries are given, so process all of them.
In each query, $2$ integers $i,\ x\ (1\ \le i \le N)$ are given. Change $A_i$ to $x$, and output the answer to the above problem for the updated $A_i\ (1\le i \le N)$.
Input
$N$ $A_1\ A_2\ \dots\ A_N$ $Q$ $i_1\ x_1$ $\vdots$ $i_Q\ x_Q$
- $1\le N\le 2\times 10^5$
- $0\le A_i\le 10^9\ (1\le i\le N)$
- $1\le Q\le 10^5$
- $1\le i_q\le N\ (1\le q \le Q)$
- $0\le x_q\le 10^9\ (1\le q\ \le Q)$
- All input values are integers.
Output
Output $Q$ lines.
On line $q$, output the answer to the problem for the $q$-th query.
Print a newline at the end.
Sample
Sample 1
Input
3 1 2 3 1 1 1
Output
4
Consider the answer to the problem when $A_i\ (1\le i \le N)$ is $1,\ 2,\ 3$.
For example, performing the operations as follows achieves the condition in $4$ operations.
- Let $k=1$. $A_i\ (1\le i\le N)$ changes to $2,\ 1,\ 2$.
- Let $k=3$. $A_i\ (1\le i\le N)$ changes to $1,\ 0,\ 3$.
- Let $k=2$. $A_i\ (1\le i\le N)$ changes to $0,\ 1,\ 2$.
- Let $k=1$. $A_i\ (1\le i\le N)$ changes to $1,\ 0,\ 1$.
The condition cannot be achieved in $3$ or fewer operations, so the answer is $4$.
Sample 2
Input
5 3 3 3 3 3 2 3 3 2 10
Output
0 8
Line $1$ of the output is the answer to the problem when $A_i\ (1\le i\le N)$ is $3,\ 3,\ 3,\ 3,\ 3$.
Line $2$ of the output is the answer to the problem when $A_i\ (1\le i\le N)$ is $3,\ 10,\ 3,\ 3,\ 3$.
Sample 3
Input
15 8 45 47 41 32 31 13 28 46 21 8 8 26 47 15 5 8 41 4 45 1 34 14 25 8 8
Output
303 303 331 317 275
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