Submission #442098

#	Time	Username	Problem	Language	Result	Execution time	Memory
442098		Evirir	Feast (NOI19_feast)	C++17	0 / 100	2 ms	332 KiB

feast

#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace std;
using namespace __gnu_pbds;

#define watch(x) cout<<(#x)<<"="<<(x)<<'\n'
#define mset(d,val) memset(d,val,sizeof(d))
#define setp(x) cout<<fixed<<setprecision(x)
#define forn(i,a,b) for(int i=(a);i<(b);i++)
#define fore(i,a,b) for(int i=(a);i<=(b);i++)
#define pb push_back
#define F first
#define S second
#define pqueue priority_queue
#define fbo find_by_order
#define ook order_of_key
typedef long long ll;
typedef pair<ll,ll> ii;
typedef vector<ll> vi;
typedef vector<ii> vii;
typedef long double ld;
template<typename T>
using pbds = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
void amin(ll &a, ll b){ a=min(a,b); }
void amax(ll &a, ll b){ a=max(a,b); }
void YES(){cout<<"YES\n";} void NO(){cout<<"NO\n";}
void SD(int t=0){ cout<<"PASSED "<<t<<endl; }
const ll INF = ll(1e18);
const int MOD = 998244353;

const bool DEBUG = 0;
const int MAXN = 300005;

int n,K;
ll a[MAXN];
ll dp[MAXN], cnt[MAXN];
ii pre[MAXN]; //best dp[j-1]+sum(j..i) for j<=i

int main()
{
	ios_base::sync_with_stdio(0); cin.tie(0);
	freopen("test.in","r",stdin);
	
	cin>>n>>K;
	int pos=0;
	fore(i,1,n)
	{
		cin>>a[i];
		if(a[i]>0) pos++;
	}
	K=min(K, pos);
	dp[0]=0;
	cnt[0]=0;
	pre[0]={-INF,0};
	
	ll ans=0;
	for(ll L=0,R=1e16;L<=R;)
	{
		ll mid=(L+R)>>1;
		
		fore(i,1,n)
		{
			ii tmp=pre[i-1];
			tmp.F+=a[i];
			pre[i]=max(tmp, {dp[i-1]+a[i]-mid, cnt[i-1]+1});
			if(pre[i].F>=dp[i-1])
			{
				dp[i]=pre[i].F;
				cnt[i]=pre[i].S;
			}
			else
			{
				dp[i]=dp[i-1];
				cnt[i]=cnt[i-1];
			}
		}
		if(cnt[n]>=K)
		{
			ans=dp[n]+min((ll)K,cnt[n])*mid;
			L=mid+1;
		}
		else R=mid-1;
		
		if(0)
		{
			cout<<"mid="<<mid<<'\n';
			cout<<"a: "; fore(i,1,n) cout<<a[i]<<" "; cout<<'\n';
			cout<<"dp: "; fore(i,1,n) cout<<dp[i]<<" "; cout<<'\n';
			cout<<"cnt: "; fore(i,1,n) cout<<cnt[i]<<" "; cout<<'\n';
			cout<<"pre: "; fore(i,1,n) cout<<"("<<pre[i].F<<","<<pre[i].S<<") "; cout<<'\n';
			cout<<"ans: "<<dp[n]+cnt[n]*mid<<"\n\n";
		}
	}
	
	cout<<ans<<'\n';
	
	return 0;
}

Compilation message (stderr)

feast.cpp: In function 'int main()':
feast.cpp:43:9: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   43 |  freopen("test.in","r",stdin);
      |  ~~~~~~~^~~~~~~~~~~~~~~~~~~~~

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