using namespace std;
struct operation
{
int x;
int y;
int o;
}op[3];
bool co=false;
void g(int a[],int b[],int n,int i,int j)
{
int x,y;
for(x=0,y=1;x<n;x++)
{
if(x==i||x==j)continue;
b[y++]=a[x];
}
op[4-n].x=a[i];
op[4-n].y=a[j];
}
void f(int a[],int n)
{
int i,j,t,b[4];
if(n==1&&a[0]==24)co=true;
for(i=0;i<n-1;i++)
{
for(j=i+1;j<n;j++)
{
for(t=1;t<=6;t++)
{
switch(t)
{
case 1:g(a,b,n,i,j);
b[0]=a[i]+a[j];
op[4-n].o=t;
f(b,n-1);
if(co)return;
break;
case 2:g(a,b,n,i,j);
b[0]=a[i]-a[j];
op[4-n].o=t;
f(b,n-1);
if(co)return;
break;
case 3:g(a,b,n,i,j);
b[0]=a[i]*a[j];
op[4-n].o=t;
f(b,n-1);
if(co)return;
break;
case 4:
if(a[j]!=0&&a[i]%a[j]==0)
{
g(a,b,n,i,j);
b[0]=a[i]/a[j];
op[4-n].o=t;
f(b,n-1);
if(co)return;
}
break;
case 5:g(a,b,n,i,j);
b[0]=a[j]-a[i];
op[4-n].o=t;
f(b,n-1);
if(co)return;
break;
case 6:
if(a[i]!=0&&a[j]%a[i]==0&&a[j]>a[i])
{
g(a,b,n,i,j);
b[0]=a[j]/a[i];
op[4-n].o=t;
f(b,n-1);
if(co)return;
}
break;
}
}
}
}
}
void h(int a[],int n,int x,int y,int h)
{
int i,j,b[4];
bool bx=false,by=false;
for(i=0,j=0;i<n;i++)
{
if(a[i]==x&&bx==false)
{
bx=true;
continue;
}
if(a[i]==y&&by==false)
{
by=true;
continue;
}
b[j++]=a[i];
}
for(i=0;i<n-1;i++)a[i+1]=b[i];
a[0]=h;
}
void main()
{
int a[4],i,j;
cout<<"輸入4個整數:";
for(i=0;i<4;i++)cin>>a[i];
f(a,4);
if(co)
{
for(i=0;i<3;i++)
{
for(j=0;j<4-i;j++)cout<<a[j]<<" ";
cout<<"\n運算 ";
switch(op[i].o)
{
case 1:cout<<op[i].x<<"+"<<op[i].y<<endl;
h(a,4-i,op[i].x,op[i].y,op[i].x+op[i].y);
break;
case 2:cout<<op[i].x<<"-"<<op[i].y<<endl;
h(a,4-i,op[i].x,op[i].y,op[i].x-op[i].y);
break;
case 3:cout<<op[i].x<<"*"<<op[i].y<<endl;
h(a,4-i,op[i].x,op[i].y,op[i].x*op[i].y);
break;
case 4:cout<<op[i].x<<"/"<<op[i].y<<endl;
h(a,4-i,op[i].x,op[i].y,op[i].x/op[i].y);
break;
case 5:cout<<op[i].y<<"-"<<op[i].x<<endl;
h(a,4-i,op[i].x,op[i].y,op[i].y-op[i].x);
break;
case 6:cout<<op[i].y<<"/"<<op[i].x<<endl;
h(a,4-i,op[i].x,op[i].y,op[i].y/op[i].x);
break;
}
}
cout<<"24"<<endl;
}
else cout<<"不能算出24"<<endl;
}