Submission #224532

#	Time	Username	Problem	Language	Result	Execution time	Memory
224532		kshitij_sodani	Feast (NOI19_feast)	C++17	71 / 100	230 ms	120168 KiB

feast

#include <iostream>
#include <bits/stdc++.h>
using namespace std;
#define a first
#define b second
#define pb push_back
typedef long long int llo;
llo mod=1000000007;
llo dp[2001][2001];
llo cost[2001][2001];
llo ma=0;
llo dnc(llo ind,llo l,llo r,llo ll,llo rr){
	llo mid=(l+r)/2;
	pair<llo,llo> best={-1,-1};
	for(llo i=ll;i<=rr;i++){
		if(i>mid){
			continue;
		}
		if(i==ll){
			if(i==0){
				best={-cost[0][mid],i};
			}
			else{
				best={-dp[i-1][ind-1]-cost[i][mid],i};
			}
		}

		else{
			best=min(best,{-dp[i-1][ind-1]-cost[i][mid],i});
		}
	}
	
	dp[mid][ind]=-best.a;

	ma=max(ma,dp[mid][ind]);
	if(mid>l){
		dnc(ind,l,mid-1,ll,best.b);
	}
	if(mid<r){
		dnc(ind,mid+1,r,best.b,rr);
	}
}
int main(){
	ios_base::sync_with_stdio(false);
	cin.tie(NULL);
	llo n,k;
	cin>>n>>k;

	llo it[n];
	for(llo i=0;i<n;i++){
		cin>>it[i];
	}
	if(k==1){
		llo su=0;
		for(int i=0;i<n;i++){
			su+=it[i];
			su=max(su,(llo)0);
			ma=max(ma,su);
		}
		cout<<ma<<endl;
		return 0;
	}
	llo ind=0;
	vector<llo> aa;
	while(ind<n){
		if(it[ind]<=0){
			llo su=0;
			while(ind<n){
				if(it[ind]>0){
					break;
				}
				su+=it[ind];
				ind+=1;
			}
			aa.pb(su);
		}
		if(it[ind]>0){
			llo su=0;
			while(ind<n){
				if(it[ind]<0){
					break;
				}
				su+=it[ind];
				ind+=1;
			}
			aa.pb(su);
		}
	}
	llo j=0;
	for(llo i=0;i<aa.size();i++){
		if(aa[i]>0){
			llo ma=0;
			llo su=0;
			llo ind=i;
			llo ind2=j;
			while(ind>=0){
				su+=aa[ind];
				ma=max(ma,su);
				if(aa[ind]>0){
					cost[ind2][j]=ma;
					ind2-=1;
				}
				ind-=1;
			}	
			j+=1;
		}
	}
	for(llo i=0;i<j;i++){
		dp[i][0]=cost[0][i];
		ma=max(ma,cost[0][i]);
	}
	for(llo jj=1;jj<min(j,k);jj++){
		dnc(jj,0,j-1,0,j-1);

	}
	cout<<ma<<endl;













	return 0;
}

Compilation message (stderr)

feast.cpp: In function 'llo dnc(llo, llo, llo, llo, llo)':
feast.cpp:42:1: warning: no return statement in function returning non-void [-Wreturn-type]
 }
 ^
feast.cpp: In function 'int main()':
feast.cpp:90:15: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for(llo i=0;i<aa.size();i++){
              ~^~~~~~~~~~

• Subtask 1: 4 / 4
• Subtask 2: 8 / 8
• Subtask 3: 18 / 18
• Subtask 4: 10 / 10
• Subtask 5: 11 / 11
• Subtask 6: 20 / 20
• Subtask 7: 0 / 29