Submission #308148

#	Time	Username	Problem	Language	Result	Execution time	Memory
308148		talant117408	Rice Hub (IOI11_ricehub)	C++17	100 / 100	20 ms	3104 KiB

ricehub

#include "ricehub.h"

#include <bits/stdc++.h>

using namespace std;

typedef long long ll;
typedef pair <int, int> pii;

#define pb push_back
#define mp make_pair
#define all(v) v.begin(),v.end()

const int N = 1e5+7;
vector <ll> pref(N), suff(N), v(N);
int n;

ll getpref(int l, int r){
    return pref[r]-1ll*(l-1)*(v[r]-v[l-1])-pref[l-1];
}

ll getsuff(int l, int r){
    return suff[l]-1ll*(n-r)*(v[r+1]-v[l])-suff[r+1];
}

bool check2(int l, int r, ll B){
    int mid = (l+r) >> 1;
    return getpref(l, mid)+getsuff(mid, r) <= B;
}

bool check(int x, ll B){
    int flag = 0;
    for(int i = 1; i+x-1 <= n; i++){
        if(check2(i, i+x-1, B)){
            flag++;
            break;
        }
    }
    return flag;
}

int besthub(int R, int L, int X[], long long B){
    n = R;
    int i;
    for(i = 0; i < R; i++){
        v[i+1] = X[i];
    }
    for(i = 1; i <= n; i++){
        pref[i] = pref[i-1]+1ll*(i-1)*(v[i]-v[i-1]);
    }
    for(i = n; i; i--){
        suff[i] = suff[i+1]+1ll*(n-i)*(v[i+1]-v[i]);
    }
    
    int l = 1, r = n;
    while(l < r){
        int mid = (l+r+1) >> 1;
        if(check(mid, B)) l = mid;
        else r = mid-1;
    }
    
    return l;
}

• Subtask 1: 17 / 17
• Subtask 2: 25 / 25
• Subtask 3: 26 / 26
• Subtask 4: 32 / 32