812C - Sagheer and Nubian Market

Sagheer and Nubian Market

 

二分+排序

比赛时没对，赛后检查才发现check（）里的参数类型是int 改成ll就对了。好气哦！

#include <bits/stdc++.h>
#define ll long long
using namespace std;
const int N = 1e5+10;
ll a[N], b[N], k, t, n, l, r, s, ans;

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

int main(){
    cin >> n >> s;
    for(int i = 1; i <= n; i ++)scanf("%lld",&a[i]);
    l = 1, r = n;
    while(l<=r){
        ll mid = (l+r)/2;
        if(check(mid)){
            k = mid;
            t = ans;
            l = mid+1;
        }else{
            r = mid-1;
        }
    }
    cout << k << " " << t << endl;
    return 0;
}