c++二十四点代码

#include<cstdio>
#include<iostream>
#include <cmath>
using namespace std;
unsigned long long int xx[1001];
int x=1;
int pd;
int f1(int a, int b, int c, int d){
    int sum;
    pd=0;
    char s1,s2,s3;
    for (int j = 1; j <= 4; j++){
        for (int k = 1; k <= 4; k++){
            for (int l = 1; l <= 4; l++){
                sum = 0;
                sum += a;
                switch (j)
                {
                case 1:sum += b; break;
                case 2:sum -= b; break;
                case 3:sum *= b; break;
                case 4:
                    if (sum%b)
                        sum = 9999;
                    else
                        sum /= b;
                break;
                default:
                    break;
                }
                switch (k){
              case 1:sum += c; break;
              case 2:sum -= c; break;
              case 3:sum *= c; break;
              case 4:
                  if (sum%c)
                      sum = 9999;
                  else
                      sum /= c;
              break;
              default:
                  break;
                }
                switch (l)
                {
                case 1:sum += d; break;
                case 2:sum -= d; break;
                case 3:sum *= d; break;
                case 4:
                    {
                        if (sum%d)
                        {
                            sum = 9999;
                        }
                        else
                        {
                            sum /= d;
                        }
                    }break;
                default:
                    break;
                }
                switch (j)
                {
                    case 1:s1='+';break;
                    case 2:s1='-';break;
                    case 3:s1='*';break;
                    case 4:s1='/';break;
                }
                switch (k)
                {
                    case 1:s2='+';break;
                    case 2:s2='-';break;
                    case 3:s2='*';break;
                    case 4:s2='/';break;
                }
                switch (l)
                {
                    case 1:s3='+';break;
                    case 2:s3='-';break;
                    case 3:s3='*';break;
                    case 4:s3='/';break;
                }
                if (sum == 24)
                {
                    if (x==0)
                    {
                        xx[x]=a*1000000+b*100000+c*10000+d*1000+j*100+k*10+l;
                        x++;
                        printf("((%d%c%d)%c%d)%c%d=24\n",a,s1,b,s2,c,s3,d);
                    }
                    else
                    {
                        for (int i=1;i<=x;i++)
                        {
                            if ((a*1000000+b*100000+c*10000+d*1000+j*100+k*10+l)==xx[i])
                            {
                                pd=1;
                                break;
                            }
                        }
                        if (pd==0)
                        {
                            xx[x]=a*1000000+b*100000+c*10000+d*1000+j*100+k*10+l;
                            x++;
                            printf("((%d%c%d)%c%d)%c%d=24\n",a,s1,b,s2,c,s3,d);
                        }
                    }
                    return 1;
                }
            }
        }
    }
    return 0;
}
int f2(int a, int b, int c, int d)
{
    int sum = 0;
    sum = f1(a, b, c, d) + f1(a, b, d, c) + f1(a, c, b, d) + f1(a, c, d, b) + f1(a, d, b, c) + f1(a, d, c, b);
    if (sum != 0)
        return 1;
    else
        return 0;
}
int main(){
    int a, b, c, d;
    int sum;
    cin >> a >> b >> c >> d;
    sum = f2(a, b, c, d) + f2(b, a, c, d) + f2(c, a, b, d) + f2(d, a, b, c);
    if (sum == 0)
        cout << "Wrong Input" << endl;
    return 0;
}