hdu 2068 错排

这几天做了好几道错排题目，这题就直接在hdu2069的代码上改了，直接过了

/*
 * hdu2068/linux.c
 * Created on: 2011-7-31
 * Author    : ben
 */
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <math.h>

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

long long ans[26][26];

void init() {
    int i, j, k;
    memset(ans, 0, sizeof(ans));
    ans[2][2] = 1;
    ans[3][3] = 2;
    ans[3][2] = 3;
    for (i = 4; i <= 25; i++) {
        ans[i][i] = (i - 1) * (ans[i - 1][i - 1] + ans[i - 2][i - 2]);
        for (j = i - 1; j > 2; j--) {
            ans[i][j] = ans[i - 1][j];
            ans[i][j] += ans[i - 1][j - 1] * (j - 1);
            ans[i][j] += ans[i - 1][j - 2] * (i - j + 1);
        }
        ans[i][2] = ans[i - 1][2] + i - 1;
    }
}
void work() {
    int T, temp;
    long long res;
    init();
    while (scanf("%d", &T) == 1 && T > 0) {
        res = 1;
        for(temp = T / 2; temp > 0; temp--) {
            res += ans[T][temp];
        }
        printf("%lld\n", res);
    }
}