Submission #697651

#	Time	Username	Problem	Language	Result	Execution time	Memory
697651		tamthegod	Split the sequence (APIO14_sequence)	C++17	100 / 100	1137 ms	83324 KiB

sequence

// Make the best become better
// No room for laziness
#include<bits/stdc++.h>

#define pb push_back
#define fi first
#define se second
using namespace std;
using ll = long long;
using ld = long double;
using ull = unsigned long long;
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
const int maxN = 1e5 + 5;
const int maxK = 205;
const int mod = 1e9 + 7;
const ll oo = 1e18;
int n, k, a[maxN];
ll sum[maxN];
ll f[maxN][2];
int trace[maxN][maxK];
void ReadInput()
{
    cin >> n >> k;
    for(int i=1; i<=n; i++)
    {
        cin >> a[i];
        sum[i] = sum[i - 1] + a[i];
    }
}
ll get(int l, int r)
{
    if(l > r) return 0;
    return sum[r] - sum[l - 1];
}
int t = 0;
void DnC(int l, int r, int optl, int optr)
{
    if(l > r) return;
    int mid = (l + r) / 2;
    ll res = -oo, id = -1;
    for(int i=optl; i<=min(mid, optr); i++)
    {
        ll cost = f[i - 1][(t & 1) ^ 1] + get(i, mid) * get(mid + 1, n);
        if(res <= cost)
        {
            res = cost;
            id = i;
        }
    }
    trace[mid][t] = id;
    f[mid][t & 1] = res;
    DnC(l, mid - 1, optl, id);
    DnC(mid + 1, r, id, optr);
}
void Solve()
{
   //cout << get(1, n);return
    memset(f, -3, sizeof f);
    f[0][0] = 0;
    for(int i=1; i<=k; i++)
    {
        t++;
        DnC(1, n, 1, n);
    }
    ll res = -1;
    int id = n;
    for(int i=k; i<=n; i++)
    {
        if(res < f[i][k & 1])
        {
            res = f[i][k & 1];
            id = i;
        }
    }
    cout << res << '\n';
    n = id;
    vector<int> ans;
    ans.pb(id);
    while(k > 1)
    {
        int id = trace[n][k] - 1;
        ans.pb(id);
        n = id;
        k--;
    }
    reverse(ans.begin(), ans.end());
    for(int v : ans)
        cout << v << " ";
}
int32_t main()
{
   // freopen("sol.inp", "r", stdin);
    //freopen("sol.out", "w", stdout);
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);
    ReadInput();
    Solve();
}

• Subtask 1: 11 / 11
• Subtask 2: 11 / 11
• Subtask 3: 11 / 11
• Subtask 4: 17 / 17
• Subtask 5: 21 / 21
• Subtask 6: 29 / 29