C++ :

#include<cstdio>
using namespace std;
int n,a[2000001],d[2000001],s=0;
int main()
{
	scanf("%d%d",&n,&a[0]);
	for(int i=1;i<=n;i++)
	{
		scanf("%d",&a[i]);
		a[i]+=a[i-1];
		d[i]=i;
	}
	for(int i=0;i<=n;i++)
	{
		int t=a[i]/100;
		if(t>=n) {printf("%d",a[n]-(d[n]+d[i])*100);return 0;}
		if(t>s)
		{
			for(int j=t;j>s;j--) 
			{
				d[j]+=d[i];
				a[j]-=d[j]*100;
			}
			s=t;
		}
	}
}