Codeforces Round 404 (Div. 2)
E
Anton and Permutation
Codeforces
2200
原题
← D→
翻译中…

Anton likes permutations, especially he likes to permute their elements. Note that a permutation of $*n*$ elements is a sequence of numbers ${*a*_{1}, *a*_{2}, ..., *a*_{*n*}}$, in which every number from $1$ to $*n*$ appears exactly once.

翻译中…

One day Anton got a new permutation and started to play with it. He does the following operation $*q*$ times: he takes two elements of the permutation and swaps these elements. After each operation he asks his friend Vanya, how many inversions there are in the new permutation. The number of inversions in a permutation is the number of distinct pairs $(*i*, *j*)$ such that $1 ≤ *i* < *j* ≤ *n*$ and $*a*_{*i*} > *a*_{*j*}$.

翻译中…

Vanya is tired of answering Anton's silly questions. So he asked you to write a program that would answer these questions instead of him.

翻译中…

Initially Anton's permutation was ${1, 2, ..., *n*}$, that is $*a*_{*i*} = *i*$ for all $*i*$ such that $1 ≤ *i* ≤ *n*$.

翻译中…

Input

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The first line of the input contains two integers $*n*$ and $*q*$ $(1 ≤ *n* ≤ 200 000, 1 ≤ *q* ≤ 50 000)$ — the length of the permutation and the number of operations that Anton does.

翻译中…

Each of the following $*q*$ lines of the input contains two integers $*l*_{*i*}$ and $*r*_{*i*}$ $(1 ≤ *l*_{*i*}, *r*_{*i*} ≤ *n*)$ — the indices of elements that Anton swaps during the $*i*$-th operation. Note that indices of elements that Anton swaps during the $*i*$-th operation can coincide. Elements in the permutation are numbered starting with one.

翻译中…

Output

翻译中…

Output $*q*$ lines. The $*i*$-th line of the output is the number of inversions in the Anton's permutation after the $*i*$-th operation.

翻译中…

Note

翻译中…

Consider the first sample.

翻译中…

After the first Anton's operation the permutation will be ${1, 2, 3, 5, 4}$. There is only one inversion in it: $(4, 5)$.

翻译中…

After the second Anton's operation the permutation will be ${1, 5, 3, 2, 4}$. There are four inversions: $(2, 3)$, $(2, 4)$, $(2, 5)$ and $(3, 4)$.

翻译中…

After the third Anton's operation the permutation will be ${1, 4, 3, 2, 5}$. There are three inversions: $(2, 3)$, $(2, 4)$ and $(3, 4)$.

翻译中…

After the fourth Anton's operation the permutation doesn't change, so there are still three inversions.

翻译中…

样例

Input #1
5 4
4 5
2 4
2 5
2 2
Output #1
1
4
3
3
InputCopy OutputCopy
Input #2
2 1
2 1
Output #2
1
InputCopy OutputCopy
Input #3
6 7
1 4
3 5
2 3
3 3
3 6
2 1
5 1
Output #3
5
6
7
7
10
11
8
InputCopy OutputCopy
题目信息
题号
785E
时间限制
4 s
内存限制
512 MB
标签
暴力
数据结构

题面与样例版权归 Codeforces 及出题人所有;中文翻译由 AI 生成(CI 管线),如有出入请以原文为准。