Submission #294552

#	Time	Username	Problem	Language	Result	Execution time	Memory
294552		nandonathaniel	Discharging (NOI20_discharging)	C++14	100 / 100	167 ms	25848 KiB

Discharging

#include <bits/stdc++.h>
using namespace std;
typedef long long LL;
typedef pair<LL,LL> pii;
const LL MAXN=1000005;
const LL INF=1e15;
vector<pii> line;
pii garis[MAXN];

pii tpot(pii satu,pii dua){
	pii ret;
	ret.first=satu.second-dua.second;
	ret.second=dua.first-satu.first;
	return ret;
}
 
bool great(pii x,pii y){
	if(x.first/x.second<y.first/y.second)return true;
	if(x.first/x.second>y.first/y.second)return false;
	return (x.first%x.second)%y.second<=(y.first%y.second)*x.second;
}

int main(){
    ios_base::sync_with_stdio(false);cin.tie(NULL);cout.tie(NULL);
    LL n,a,maxVal=0,last=0;
    cin >> n;
    garis[1]={-1,0};  //-i,dp[i-1]
    for(LL i=1;i<=n;i++){
    	cin >> a;
    	if(a>=maxVal){
    		maxVal=a;
    		for(LL j=last+1;j<=i;j++){
    			LL skg=line.size()-1,prev=line.size()-2;
				while(skg>0 && great(tpot(garis[j],line[skg]),tpot(garis[j],line[prev]))){
					line.pop_back();
					skg--;
					prev--;
				}
				line.push_back(garis[j]);
			}
    		last=i;
		}
		LL x=maxVal;
		LL dpVal;
		if(line.size()==1)dpVal=1LL*x*line[0].first+line[0].second;
		else{
			LL ki=1,ka=line.size()-1;
			dpVal=INF;
			while(ki<=ka){
				LL mid=(ki+ka)/2;
				LL kiri=1LL*x*line[mid-1].first+line[mid-1].second;
				LL kanan=1LL*x*line[mid].first+line[mid].second;
				dpVal=min(dpVal,min(kiri,kanan));
				if(kanan<kiri)ki=mid+1;
				else ka=mid-1;
			}
		}
		dpVal+=(1LL*maxVal*(n+1));
		garis[i+1]={-(i+1),dpVal};
	}
	cout << garis[n+1].second << '\n';
    return 0;
}

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