Submission #949501

#	Time	Username	Problem	Language	Result	Execution time	Memory
949501		PM1	Split the sequence (APIO14_sequence)	C++17	100 / 100	548 ms	83608 KiB

sequence

#include <bits/stdc++.h>
using namespace std;
#define ll long long
const int mxn=1e5+5,mxk=205;
int n,k,aa[mxn];
int par[mxn][mxk];
ll dp[mxn][2],pre[mxn],ans;
deque<int>cht;
bool comp(int x,int y,ll w,bool z){
	ll xx=(-pre[x])*w+dp[x][z],yy=(-pre[y])*w+dp[y][z];
	return xx>yy;
}
bool cmp(int x,int y,int w,bool z){
	return (dp[w][z]-dp[y][z])*(pre[y]-pre[x])<(dp[y][z]-dp[x][z])*(pre[w]-pre[y]);
}
int main(){
	cin>>n>>k;
	for(int i=1;i<=n;i++){
		cin>>aa[i];
		pre[i]=pre[i-1]+aa[i];
	}
	for(int i=1;i<=n;i++){
		dp[i][1]=pre[i]*(pre[n]-pre[i]);
	}
	for(int j=2;j<=k;j++){
		bool y=j&1;
		cht.push_back(j-1);
		for(int i=j;i<n;i++){
			//ax+b
			ll x=pre[n]-pre[i];
			while(cht.size()>1 && !comp(cht[0],cht[1],x,y^1))cht.pop_front();
			ll a=-pre[cht[0]],b=dp[cht[0]][y^1];
			dp[i][y]=a*x+b+pre[i]*x;
			par[i][j]=cht[0];
			while(cht.size()>1 && !cmp(cht[cht.size()-2],cht.back(),i,y^1))cht.pop_back();
			cht.push_back(i);
			
		}//cout<<'\n';
		cht.clear();
	}
	for(int i=1;i<n;i++){
		int y=k&1;
		if(dp[i][y]>=dp[ans][y])ans=i;
	}
	cout<<dp[ans][k&1]<<'\n';
	vector<int>v;
	while(ans!=0){
		v.push_back(ans);
		ans=par[ans][k];
		k--;
	}
	reverse(v.begin(),v.end());
	for(auto i:v){
		cout<<i<<" ";
	}
	return 0;
}

• Subtask 1: 11 / 11
• Subtask 2: 11 / 11
• Subtask 3: 11 / 11
• Subtask 4: 17 / 17
• Subtask 5: 21 / 21
• Subtask 6: 29 / 29