Submission #90037

#	Time	Username	Problem	Language	Result	Execution time	Memory
90037		KLPP	Split the sequence (APIO14_sequence)	C++14	71 / 100	2041 ms	83940 KiB

sequence

#include<stdio.h>
#include<iostream>
#include<deque>
#include<queue>
using namespace std;
typedef long long int lld;
#define INF 1000000000000000000
typedef pair<lld,lld> line;

int pre[100001][202];
lld sq(lld x){
	return x*x;
}
class CH{
	deque<pair<line,int> > d;
	public:
	void print(){
		queue<pair<line,int> >q;
		while(!d.empty()){
			q.push(d.front());
			cout<<d.front().first.first<<" "<<d.front().first.second<<" "<<d.front().second<<endl;
			d.pop_front();
		}
		while(!q.empty()){
			d.push_back(q.front());
			q.pop();
		}
	}
	double intersect(pair<line,int> a, pair<line,int> b){
		return (double)(a.first.first-b.first.first)/(b.first.second-a.first.second);
	}
	void add(line l, int index){
		pair<line,int> P;
		P.first=l;
		P.second=index;
		while(d.size()>0 && P.first.second==d.back().first.second){
			if(P.first.first<d.back().first.first){
				d.pop_back();
			}else{
				return;
			}
		}
		if(d.size()<2){
			d.push_back(P);
			return;
		}
		pair<line,int> A;
		pair<line,int> B;
		do{
			A=d.back();
			d.pop_back();
			B=d.back();
			//cout<<intersect(P,A)<<" "<<intersect(P,B)<<endl;
		}while(d.size()>1 && intersect(P,A)<=intersect(P,B));
		if(intersect(P,A)>intersect(P,B))d.push_back(A);
		d.push_back(P);
	}
	int size(){
		return d.size();
	}
	int query(lld c){
		if(d.size()==1){
			return d.front().second;
		}
		pair<line,int> A;
		pair<line,int> B;
		do{
			A=d.front();
			d.pop_front();
			B=d.front();
		}while(d.size()>1 && intersect(A,B)<=c);
		if(intersect(A,B)>c)d.push_front(A);
		return d.front().second;
	}
	void clear(){
		while(!d.empty())d.pop_back();
	}
};
int main(){
	int n,k;
	scanf("%d %d",&n,&k);
	lld arr[n];
	lld acc[n+1];
	acc[0]=0;
    	for(int i=0;i<n;i++){
    		scanf("%lld",&arr[i]);
		acc[i+1]=acc[i]+arr[i];
    	}
	lld DP[n+1];
    	for(int i=0;i<=n;i++){
    		DP[i]=-1;
    	}
    	DP[0]=0;
	CH *C=new CH();
    	for(int parts=0;parts<=k;parts++){
		for(int i=parts;i<=n;i++){
			if(i>parts){
				pre[i][parts+1]=C->query(acc[i]);
				//N[i]=DP[pre[i][parts+1]]+sq(acc[i]-acc[pre[i][parts+1]]);
			}
			if(DP[i]!=-1){
				C->add(line(sq(acc[i])+DP[i],-2*acc[i]),i);
			}
		}
		C->clear();
		for(int i=n;i>-1;i--)DP[i]=DP[pre[i][parts+1]]+sq(acc[i]-acc[pre[i][parts+1]]);
		DP[parts]=-1;
		/*for(int i=0;i<=n;i++)cout<<DP[i]<<" ";
		cout<<endl;*/
    	}
    	lld ans=sq(acc[n])-DP[n];
    	ans/=2;
    	printf("%lld\n",ans);
    	int index=n;
    	int partition=k+1;
    	while(partition>0){
    		index=pre[index][partition];
    		partition--;
    		if(index>0){
			printf("%d ",index);
		}
    	}
    	printf("\n");
     
	return 0;
}

Compilation message (stderr)

sequence.cpp: In function 'int main()':
sequence.cpp:81:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d %d",&n,&k);
  ~~~~~^~~~~~~~~~~~~~~
sequence.cpp:86:12: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
       scanf("%lld",&arr[i]);
       ~~~~~^~~~~~~~~~~~~~~~

• Subtask 1: 11 / 11
• Subtask 2: 11 / 11
• Subtask 3: 11 / 11
• Subtask 4: 17 / 17
• Subtask 5: 21 / 21
• Subtask 6: 0 / 29