Submission #848145

#	Time	Username	Problem	Language	Result	Execution time	Memory
848145		asd12343	Feast (NOI19_feast)	C++14	45 / 100	28 ms	48256 KiB

feast

#pragma GCC optimize("Os")
#include <bits/stdc++.h>
using namespace std;
const int MN = 2e6+5;
const int INF = 0x3f3f3f3f;
#define int long long
#define pb push_back
#define p make_pair	
#define fi first
#define se second
#define pii pair<int,int>
#define f(i,a,b) for (int i = a ; i < b ; i++)
#define f1(i,a,b) for (int i = a ; i > b ; i--)
#define f2(i,a,b) for (int i = a ; i <= b ; i++)
#define FILE(X)						\
	freopen(#X ".INP","r",stdin);	\
	freopen(#X ".OUT","w",stdout);

mt19937 rd(chrono::steady_clock::now().time_since_epoch().count());
int random(int l, int r) { return l + rd() % (r - l + 1); }
int a[MN];
int n,k,pos;
int cnt = 0;
int dp[5003][5003];
int pre[MN];
signed main(){
 	ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    //FILE(BLUESKY);
    bool flag = false;
    cin >> n >> k;
    for (int i = 1 ; i <= n ; i++) {
    	cin >> a[i];
    	pre[i] = pre[i-1] + a[i];
    	if (a[i] < 0) flag = true,cnt++, pos = i;
    }	
    if (flag == false) cout << accumulate(a+1,a+n+1,0LL);
    else if (cnt == 1) {
    	if (k == 1) {
    		int sum = 0, sum2 = 0;
    		for (int i = 1 ; i < pos ; i++) sum += a[i];
    		for (int i = pos+1 ; i <= n ; i++) sum2 += a[i];
    		cout << max(sum,sum2) << "\n";
    	}
    	else {
    		cout << accumulate(a+1,a+n+1,0LL) - a[pos];
    	}
    }
    else if (cnt == n) cout << 0;
    else if (n <= 5000) {
    	for (int i = 1; i <= k; ++i){
	        int cur = 0;
	        for (int j = 1; j <= n; ++j) {
	            cur = max(cur, dp[i-1][j] - pre[j]);
	            dp[i][j] = max(dp[i][j-1], cur + pre[j]);
	        }
    	}
    	cout << dp[k][n];
    }
    return 0;
} 

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