USACO 1.3 crypt1

水题，加了一点点剪枝，有些没用的语句其实是为了调试来着，不过没用着

/*ID:zizz-zi1LANG:CTASK:crypt1*/#include <stdio.h>int a[10],n;int check(int num){int i;for(i=0;i<n;i++)if(num==a[i]) return 1;return 0;}int main(void){FILE *fin,*fout;fin=fopen("crypt1.in","r");fout=fopen("crypt1.out","w");int ans=0,flag,l1,l2,l3,l4,l5,layer[6][5],i,j,tmp;fscanf(fin,"%d",&n);for(i=0;i<n;i++)fscanf(fin,"%d",&a[i]);for(l1=0;l1<n;l1++)for(l2=0;l2<n;l2++)for(l3=0;l3<n;l3++)for(l4=0;l4<n;l4++){if(a[l4]*a[l3]>=10) continue;layer[1][1]=a[l1];layer[1][2]=a[l2];layer[1][3]=a[l3];layer[2][1]=a[l4];layer[3][1]=(a[l4]*a[l1]);layer[3][2]=layer[3][1]/10+a[l4]*a[l2];layer[3][1]%=10;layer[3][3]=layer[3][2]/10+a[l4]*a[l3];layer[3][2]%=10;flag=1;for(i=1;i<=3;i++)if(!check(layer[3][i])) flag=0;if (!flag) continue;for(l5=0;l5<n;l5++){if(a[l5]*a[l3]>=10) continue;layer[2][2]=a[l5];layer[4][1]=(a[l5]*a[l1]);layer[4][2]=layer[4][1]/10+a[l5]*a[l2];layer[4][1]%=10;layer[4][3]=layer[4][2]/10+a[l5]*a[l3];layer[4][2]%=10;flag=1;for(j=1;j<=3;j++)if(!check(layer[4][j])) flag=0;if(!flag) continue;layer[5][1]=layer[3][1];layer[5][2]=layer[3][2]+layer[4][1];layer[5][3]=layer[5][2]/10+layer[3][3]+layer[4][2];layer[5][2]%=10;layer[5][4]=layer[5][3]/10+layer[4][3];layer[5][3]%=10;for(j=1;j<=4;j++)if(!check(layer[5][j])) flag=0;if(!flag) continue;ans++;}}fprintf(fout,"%d\n",ans);fclose(fin);fclose(fout);return 0;}