Submission #791493

#	Time	Username	Problem	Language	Result	Execution time	Memory
791493		NguyenKhang	Feast (NOI19_feast)	C++17	30 / 100	28 ms	4972 KiB

feast

//#pragma GCC optimize("Ofast,unroll-loops")
//#pragma GCC target("bmi,bmi2,lzcnt,popcnt")
//#pragma GCC target("avx2,popcnt,lzcnt,abm,bmi,bmi2,fma,tune=native")
//#pragma expected_value
//#pragma isolated_call
//#pragma disjoint

#include<bits/stdc++.h>
//#include <ext/pb_ds/assoc_container.hpp>

//using namespace __gnu_pbds;
using namespace std;

#define int long long
//#define double long double
#define Fi first
#define Se second
#define Rep(i,a,b) for (int i=a;i<=b;++i)
#define Repu(i,b,a) for (int i=b;i>=a;--i)
#define pb push_back
#define ms(a,i) memset(a,i,sizeof(a))
#define sz size()
#define mp make_pair
#define endl '\n'
#define sef setprecision(6)<<fixed
#define cer cout<<"cak"<<endl;

typedef pair<int,int> ii;
typedef vector<int> vi;
typedef vector<double> va;
typedef vector<ii> vii;
typedef vector<vi> vvi;
typedef vector<va> vva;

//const double EPS=1e-9;
const double PI=acos(-1);
const long long oo=1e18;
const int MN=3e5+5;
const int mod=1e9+7;

using cd=complex<double>;

//typedef tree<int,null_type,less<int>,rb_tree_tag, tree_order_statistics_node_update> index_set;

mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());

int n,k;
int a[MN];
int pre[MN];

int dp_before[MN], dp_now[MN];

void compute(int l,int r,int tl,int dr) {
	if(l>r) return;
	int mid = (l+r)/2;
	ii maxx = {dp_before[mid], mid};
	Rep(i,tl,min(dr,mid)) {
		int temp = pre[mid] - pre[i];
		maxx = max(maxx, ii(dp_before[i] + temp,i));
	}

	dp_now[mid] = maxx.Fi;
	compute(l,mid-1,tl,maxx.Se); compute(mid+1,r,maxx.Se,dr);
}

signed main() {
  	//freopen(".inp","r",stdin); freopen(".out","w",stdout);
  	
	ios_base::sync_with_stdio(false);
	cin.tie(NULL);
	cout.tie(NULL);

	cin>>n>>k;
	if(n<=2000) {
		Rep(i,1,n) cin>>a[i];
		Rep(i,1,n) pre[i] = pre[i-1] + a[i];

		int cek = 0;

		Rep(step,1,k) {
			Rep(i,1,n) {
				dp_now[i] = dp_before[i];
				Rep(j,0,i) dp_now[i] = max(dp_now[i], dp_before[j-1] + max(pre[i] - pre[j],cek));
			}
			Rep(i,1,n) dp_before[i] = dp_now[i];
		}
		int ans = 0;
		Rep(i,1,n) ans = max(ans,dp_before[i]);
		return 0;
	}

	int cnt = 0;
	Rep(i,1,n) {
		cin>>a[i];
		if(a[i] < 0) cnt++;
	}

	if(cnt == 0) {
		int sum = 0;
		Rep(i,1,n) {
			sum += a[i];
		}
		cout<<sum;
		return 0;
	}

	else {
		if(k==1) {
			int ans = 0;
			Rep(i,1,n) {
				dp_now[i] = max(dp_now[i-1] + a[i], a[i]);
				ans = max(ans,dp_now[i]);
			}
			cout<<ans;
		}
		else {
			int sum = 0;
			Rep(i,1,n) {
				if(a[i]<0) continue;
				sum += a[i];
			}
			cout<<sum;
		}
	}
}

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