fake_coin.c

//http://polynomialtimes.com/algorithms/decrease-and-conquer/fake-coin-algorithm/
#include<stdio.h>
#include<conio.h>
char a[10],c1[10],c2[10],c3[10];
int w[10],n,i,m,sum1=0,sum2=0,sum3=0,tot,k,b[10],c[10],d[10],k1=0,k2=0,k3=0;
void min(int f[],int k,char r[])
{
   for( i=0;i<k-1;i++)
    {
        if(f[i]>f[i+1])
        {
            m=f[i+1];

        }
    }
      printf("\nfake coin is: %c  Weight:%d",r[i-1],m);

    }


void main()
{
   printf("Enter the number of coins:");
    scanf("%d",&n);
    printf("Enter the coins:");
    for(i=0;i<n;i++)
    scanf("%s",&a[i]);
    printf("Enter the corresponding weights:");
     for(i=0;i<n;i++)
    scanf("%d",&w[i]);
    k=n/3;
    for(i=0;i<k;i++)
    {
        c1[k1]=a[i];
        sum1+=w[i];
        b[k1]=w[i];
        k1++;
    }
for(i=k;i<n-k;i++)
{
    c2[k2]=a[i];
    sum2+=w[i];
    c[k2]=w[i];
    k2++;
}
for(i=(n-k);i<=n-1;i++)
{
    c3[k3]=a[i];
    sum3+=w[i];
    d[k3]=w[i];
    k3++;
}

printf("sum1:%d",sum1);
printf("sum2=%d",sum2);
printf("sum3=%d",sum3);
if(sum1==sum2&&sum2==sum3)
   {


   printf("no fake coins");
   }

else if (sum1==sum2)
{
    min(d,k3,c3);

}
else
{

if(sum1>sum2)
{
min(c,k2,c2);

}
else
{
min(b,k1,c1);
}
}
}