hdu 1394 水题

本来以为是求逆序数，要用归并排序，而且还得用线段树动态维护神马的，睁大眼睛一看，我滴妈呀，n才5000，直接暴力过了~~

/*
 * hdu1394/linux.cpp
 * Created on: 2011-9-6
 * Author    : ben
 */
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <cmath>
#include <algorithm>
using namespace std;

const int MAXN = 5010;
int num[MAXN], reserve[MAXN];

void work();
int main() {
#ifndef ONLINE_JUDGE
    freopen("data.in", "r", stdin);
#endif
    work();
    return 0;
}

void work() {
    int N, totalres, temp;
    while (scanf("%d\n", &N) == 1) {
        for (int i = 0; i < N; i++) {
            scanf("%d", &num[i]);
        }
        totalres = 0;
        memset(reserve, 0, sizeof(reserve));
        for (int i = 0; i < N; i++) {
            for (int j = i + 1; j < N; j++) {
                if (num[i] > num[j]) {
                    reserve[i]++;
                }
            }
            totalres += reserve[i];
        }
        temp = totalres;
        for (int i = 0; i < N; i++) {
            temp += N - 2 * reserve[i] - 1;
            if (temp < totalres) {
                totalres = temp;
            }
            for (int j = i + 1; j < N; j++) {
                if (num[j] > num[i]) {
                    reserve[j]++;
                }
            }
        }
        printf("%d\n", totalres);
    }
}