
ZOJ Problem Set  2386
In this problem, you have to analyze a particular sorting algorithm. The algorithm processes a sequence of n distinct integers by swapping two adjacent sequence elements until the sequence is sorted in ascending order. For the input sequence 9 1 0 5 4 , UltraQuickSort produces the output 0 1 4 5 9 . Your task is to determine how many swap operations UltraQuickSort needs to perform in order to sort a given input sequence. Input The input contains several test cases. Every test case begins with a line that contains a single integer n < 500,000  the length of the input sequence. Each of the the following n lines contains a single integer 0 <= a[i] <= 999,999,999, the ith input sequence element. Input is terminated by a sequence of length n = 0. This sequence must not be processed. Output For every input sequence, your program prints a single line containing an integer number op, the minimum number of swap operations necessary to sort the given input sequence. Sample Input
5 Sample Output
6 Source: University of Waterloo Local Contest 2005.02.05 