UVa 10038 Jolly Jumpers Solution

#include<stdio.h>
#include <stdlib.h>

int main(){
    int i,a[3002],chk[3002],f,n,min,pdiff,ldiff,se,in;

 while(scanf("%d",&n)!=EOF){
     f=1;
     min=99999;
     for(i=0;i<=n;i++)
     chk[i]=0;


     scanf("%d",&a[0]);
     for(i=1;i<n;i++){
      scanf("%d",&a[i]);
      in=abs(a[i]-a[i-1]);
      if(chk[in]||in>=n) f=0;
      else chk[in]=1;
      if(in<min)min=in;
     }


     for(i=min+1,se=0;i<n && f;i++){
        if(chk[i]){
            pdiff=i-min;
            min=i;
            if(se) {
               if (pdiff!=ldiff) f=0;
               ldiff=pdiff;
               se=1;
          }
         }
        }


     if(f)printf("Jolly\n");
     else printf("Not jolly\n");
 }
 return 0;
}