cf 11a Increasing Sequence

#include <iostream>#include <cstdio>using namespace std;#define LL long long#define ULL unsigned long longint main(){    int n,d;    ULL ans=0;    LL b[2005];    scanf("%d%d",&n,&d);    for(int i=0;i<n;i++)        scanf("%I64d",&b[i]);    for(int i=1;i<n;i++)        if(b[i]<=b[i-1])        {            if(b[i]==b[i-1])            {                ans+=1;                b[i]+=d;            }            else            {                int tmp=(b[i-1]-b[i])/d+1;                ans+=tmp;                b[i]+=tmp*d;            }        }    printf("%I64d\n",ans);    return 0;}