【二分】Codeforces Round #417 (Div. 2) C. Sagheer and Nubian Market

傻逼二分

#include<cstdio>
#include<algorithm>
using namespace std;
typedef long long ll;
ll a[100010],b[100010],sum;
int n,m;
bool check(int x){
	for(int i=1;i<=n;++i){
		b[i]=a[i]+(ll)i*(ll)x;
	}
	sum=0;
	sort(b+1,b+n+1);
	for(int i=1;i<=x;++i){
		sum+=b[i];
	}
	return sum<=(ll)m;
}
int main(){
	scanf("%d%d",&n,&m);
	for(int i=1;i<=n;++i){
		scanf("%I64d",&a[i]);
	}
	int l=0,r=n;
	while(l<r){
		int mid=(l+r+1>>1);
		if(check(mid)){
			l=mid;
		}
		else{
			r=mid-1;
		}
	}
	check(l);
	printf("%d %I64d\n",l,sum);
	return 0;
}