poj1804

简单题

#include <iostream>
#include <cstdio>
#include <cstdlib>
#include <cstring>
using namespace std;

#define maxn 1006

int n;
int a[maxn], cnt, c[maxn];

void input()
{
    scanf("%d", &n);
    for (int i = 0; i < n; i++)
        scanf("%d", &a[i]);
}

void MergeSort(int l, int r)
{
    int mid, i, j, tmp;
    if (r > l + 1)
    {
        mid = (l + r) / 2;
        MergeSort(l, mid);
        MergeSort(mid, r);
        tmp = l;
        for ( i = l, j = mid;  i < mid && j < r; )
        {
            if (a[i] > a[j])
            {
                c[tmp++] = a[j++];
                cnt += mid - i;
            }
            else
                c[tmp++] = a[i++];
        }
        if (j < r)
            for (; j < r; ++j)
                c[tmp++] = a[j];
        else
            for(; i < mid; ++i)
                c[tmp++] = a[i];
        for (i = l; i < r; ++i)
            a[i] = c[i];
    }
}

int main()
{
    //freopen("t.txt", "r", stdin);
    int t;
    scanf("%d", &t);
    for (int i = 0; i < t; i++)
    {
        input();
        cnt = 0;
        MergeSort(0, n);
        printf("Scenario #%d:\n%d\n\n", i + 1, cnt);
    }
    return 0;
}