根据错排公式f[n]=(n-1)*(f[n-1]+f[n-2]) f[1]=0,f[2]=1

import java.io.BufferedInputStream; import java.math.BigInteger; import java.util.Scanner; public class Main {
   public static void main(String[] args) {
                   Scanner cin = new Scanner(new BufferedInputStream(System.in)); int nlen = 1001, i, n;                 BigInteger[] num = new BigInteger[nlen];                 num[1] = BigInteger.ZERO;                 num[2] = BigInteger.ONE; for (i = 3; i < nlen; i++) {
                           num[i] = num[i - 1].add(num[i - 2]).multiply(                                         BigInteger.valueOf(i - 1));                 } while (cin.hasNext()) {
                           n = cin.nextInt();                         System.out.println(num[n]);                 }         } }

打表部分代码如下所示：

/*  * wrongsort.cpp  *  *  Created on: 2011-10-10  *      Author: bjfuwangzhu */ #include
     
       #include
      
        #include
       
         using namespace std; const int nmax = 1001; string num[nmax]; int main() {
   #ifndef ONLINE_JUDGE     freopen("data.in", "r", stdin); #endif int i, n;     num[1] = "0";     num[2] = "1";     num[3] = "2";     num[4] = "9";     num[5] = "44";     num[6] = "265";     num[7] = "1854";     num[8] = "14833";     num[9] = "133496";     num[10] = "1334961";     num[11] = "14684570";     num[12] = "176214841";     num[13] = "2290792932";     num[14] = "32071101049";     num[15] = "481066515734";     num[16] = "7697064251745";     num[17] = "130850092279664";     num[18] = "2355301661033953";     num[19] = "44750731559645106";     num[20] = "895014631192902121";     num[21] = "18795307255050944540";     num[22] = "413496759611120779881";     num[23] = "9510425471055777937262";     num[24] = "228250211305338670494289";     num[25] = "5706255282633466762357224";     num[26] = "148362637348470135821287825";     num[27] = "4005791208408693667174771274";     num[28] = "112162153835443422680893595673";     num[29] = "3252702461227859257745914274516";     num[30] = "97581073836835777732377428235481";     num[31] = "3025013288941909109703700275299910";     num[32] = "96800425246141091510518408809597121";     num[33] = "3194414033122656019847107490716704992";     num[34] = "108610077126170304674801654684367969729";     num[35] = "3801352699415960663618057913952878940514";     num[36] = "136848697178974583890250084902303641858505";     num[37] = "5063401795622059603939253141385234748764684";     num[38] = "192409268233638264949691619372638920453057993";     num[39] = "7503961461111892333037973155532917897669261726";     num[40] = "300158458444475693321518926221316715906770469041";     num[41] = "12306496796223503426182275975073985352177589230680";     num[42] = "516872865441387143899655590953107384791458747688561";     num[43] = "22225533213979647187685190410983617546032726150608122";     num[44] = "977923461415104476258148378083279172025439950626757369";     num[45] = "44006555763679701431616677013747562741144797778204081604";     num[46] = "2024301565129266265854367142632387886092660697797387753785";     num[47] = "95142173561075514495155255703722230646355052796477224427894";     num[48] = "4566824330931624695767452273778667071025042534230906772538913";     num[49] = "223774392215649610092605161415154686480227084177314431854406736"; ----------------------------- while (scanf("%d", &n) != EOF) {
           cout << num[n] << endl;     } return 0; }