codeforces 812C——Sagheer and Nubian Market（二分）

C. Sagheer and Nubian Market

time limit per test
2 seconds

memory limit per test
256 megabytes

input
standard input

output
standard output

On his trip to Luxor and Aswan, Sagheer went to a Nubian market to buy some souvenirs for his friends and relatives. The market has some strange rules. It contains n different
items numbered from 1 to n.
The i-th item has base cost ai Egyptian
pounds. If Sagheer buys kitems with indices x1, x2, ..., xk,
then the cost of item xj is axj + xj·k for 1 ≤ j ≤ k.
In other words, the cost of an item is equal to its base cost in addition to its index multiplied by the factor k.

Sagheer wants to buy as many souvenirs as possible without paying more than S Egyptian pounds. Note that he cannot buy a souvenir more
than once. If there are many ways to maximize the number of souvenirs, he will choose the way that will minimize the total cost. Can you help him with this task?

Input

The first line contains two integers n and S (1 ≤ n ≤ 105 and 1 ≤ S ≤ 109) —
the number of souvenirs in the market and Sagheer's budget.

The second line contains n space-separated integers a1, a2, ..., an (1 ≤ ai ≤ 105) —
the base costs of the souvenirs.

Output

On a single line, print two integers k, T —
the maximum number of souvenirs Sagheer can buy and the minimum total cost to buy these ksouvenirs.

Examples

input

3 11
2 3 5

output

2 11

input

4 100
1 2 5 6

output

4 54

input

1 7
7

output

0 0

Note

In the first example, he cannot take the three items because they will cost him [5, 9, 14] with total cost 28.
If he decides to take only two items, then the costs will be [4, 7, 11]. So he can afford the first and second items.

In the second example, he can buy all items as they will cost him [5, 10, 17, 22].

In the third example, there is only one souvenir in the market which will cost him 8 pounds, so he cannot buy it.

简单二分。看代码吧..

#include <iostream>
#include <cstdio>
#include <algorithm>
#include <cmath>
#include <cstring>
#include <string>
#include <vector>
#include <map>
#include <set>
using namespace std;

#define _ sync_with_stdio(false)
typedef long long ll;
const int MAXN=100000+10;
const long long INF=0x7fffffffffffffff;

long long s[MAXN];
long long a[MAXN];

int n,S;
long long ans=0;
bool C(long long x){
if(x>n){
return false;
}
for(int i=1;i<=n;i++){
s[i]=a[i]+i*x;
}
sort(s+1,s+n+1);
long long temp=0;
for(int i=1;i<=x;i++){
temp+=s[i];
}
if(temp<=S){
ans=temp;
return true;
}else{
return false;
}
}

int main(){
scanf("%d%d",&n,&S);
for(int i=1;i<=n;i++){
scanf("%lld",a+i);
}
long long l=0;
long long r=n+1;
while(r>l+1){
long long m=(l+r)>>1;
if(C(m)){
l=m;
}else{
r=m;
}
}
printf("%I64d %I64d\n",l,ans);
}