Submission #1140845

#	Time	Username	Problem	Language	Result	Execution time	Memory
1140845		Luvidi	Discharging (NOI20_discharging)	C++17	100 / 100	84 ms	15944 KiB

Discharging

#include <bits/stdc++.h>
using namespace std;

#define ll long long
#define pll pair<ll, ll>
#define pii pair<int, int>
#define fs first
#define sc second
#define pb push_back

double ins(pll p1,pll p2){
    double x=p1.sc-p2.sc,y=p2.fs-p1.fs;
    return x/y;
}

void solve() {
    int n;
    cin>>n;
    ll a[n+1];
    for(int i=1;i<=n;i++)cin>>a[i];
    vector<pll> ch;
    ll dp[n+1];
    dp[0]=0;
    int idx=0,lg=0;
    for(int i=1;i<=n;i++){
        if(!lg||a[i]>a[lg]){
            for(int j=lg+1;j<=i;j++){
                pll p={n-j+1,dp[j-1]};
                while(ch.size()>1&&ins(ch[ch.size()-2],ch.back())>ins(ch.back(),p))ch.pop_back();
                ch.push_back(p);
            }
            lg=i;
        }        
        idx=min(idx,(int)ch.size()-1);
        while(idx+1<ch.size()&&ins(ch[idx],ch[idx+1])<a[lg])idx++;
        dp[i]=ch[idx].fs*a[lg]+ch[idx].sc;
    }
    cout<<dp[n]<<'\n';
}

int main() {
    #ifdef FPO
        freopen("in","r",stdin);
        freopen("out","w",stdout);
    #endif
    ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);

    solve();
}

• Subtask 1: 9 / 9
• Subtask 2: 13 / 13
• Subtask 3: 25 / 25
• Subtask 4: 11 / 11
• Subtask 5: 14 / 14
• Subtask 6: 28 / 28