Submission #1101092

#	Time	Username	Problem	Language	Result	Execution time	Memory
1101092		trie	Feast (NOI19_feast)	C++17	71 / 100	114 ms	104188 KiB

feast

#include<bits/stdc++.h>
#define mp make_pair
#define fi first
#define se second
#define ii pair<int, int>
#define iii pair<ii, int>
#define ll long long
#define pb push_back
#define pli pair<ll, int>
#define all(v) (v).begin(), (v).end()
#define uniquev(v) sort(all(v)), (v).resize(unique(all(v)) - (v).begin())
#define cntbit(mask) __builtin_popcount(mask)
#define getbit(x, i) ((x >> i) & 1)
#define MASK(i) (1 << i)
#define pli pair<ll, int>
using namespace std;

template<class T1, class T2>
bool maximize(T1 &a, T2 b){if(a < b){a = b; return 1;} return 0;}

template<class T1, class T2>
bool minimize(T1 &a, T2 b){if(a > b){a = b; return 1;} return 0;}

const int N = 2005;
const int V = 3e5 + 5;
const int MOD = 1e9 + 7;

int n, k;
ll pr[V], dp[N][N], mx[N][N], a[V];
int negative, idx;

void solve() {
    cin >> n >> k;
    for(int i = 1 ; i <= n ; i++) {
        cin >> a[i];
        pr[i] = pr[i - 1] + a[i];
        if (a[i] < 0) {
            negative++;
            idx = i;
        }
    }

    if (!negative) return cout << pr[n], void();
    if (k == 1) { // kadane algorithm.
        ll sum = 0, mxsum = 0;
        for(int i = 1 ; i <= n ; i++) {
            sum += a[i];
            maximize(mxsum, sum);
            if (sum < 0) sum = 0;
        }
        return cout << mxsum, void();
    }
    if (negative == 1) return cout << pr[n] - a[idx], void();

    for(int i = 1 ; i <= n ; i++) mx[i][0] = max(mx[i - 1][0], - pr[i]);

    for(int i = 1 ; i <= n ; i++)
        for(int j = 1 ; j <= n ; j++) {
            dp[i][j] = dp[i - 1][j];
            maximize(dp[i][j], mx[i][j - 1] + pr[i]);
            mx[i][j] = max(mx[i - 1][j], dp[i][j] - pr[i]);
        }

    cout << dp[n][k];
}

int main(void) {
    //freopen("task.inp", "r", stdin);
    //freopen("task.out", "w", stdout);
	ios_base::sync_with_stdio(false);
	cin.tie(0); cout.tie(0);
    int t = 1; while(t--) solve();
    return 0;
}

• 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