302787: CF540E. Infinite Inversions
Memory Limit:256 MB
Time Limit:2 S
Judge Style:Text Compare
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Description
Infinite Inversions
题意翻译
现在有一个由所有正整数组成的无限递增序列: $p = {1,2,3,...}$ 。 对这个序列执行 $n$ 次交换操作。每次一个操作,给出两个整数 $a,b$ ,交换位置 $a$ 和 $b$ 处的元素。 你的任务是在所有操作结束后,输出最终序列的逆序对个数,即满足 $i < j$ 且 $p_i > p_j$ 的有序数对 $(i,j)$ 的数量。题目描述
There is an infinite sequence consisting of all positive integers in the increasing order: $ p={1,2,3,...} $ . We performed $ n $ swap operations with this sequence. A $ swap(a,b) $ is an operation of swapping the elements of the sequence on positions $ a $ and $ b $ . Your task is to find the number of inversions in the resulting sequence, i.e. the number of such index pairs $ (i,j) $ , that $ i<j $ and $ p_{i}>p_{j} $ .输入输出格式
输入格式
The first line contains a single integer $ n $ ( $ 1<=n<=10^{5} $ ) — the number of swap operations applied to the sequence. Each of the next $ n $ lines contains two integers $ a_{i} $ and $ b_{i} $ ( $ 1<=a_{i},b_{i}<=10^{9} $ , $ a_{i}≠b_{i} $ ) — the arguments of the swap operation.
输出格式
Print a single integer — the number of inversions in the resulting sequence.
输入输出样例
输入样例 #1
2
4 2
1 4
输出样例 #1
4
输入样例 #2
3
1 6
3 4
2 5
输出样例 #2
15