Submission #790131

#	Time	Username	Problem	Language	Result	Execution time	Memory
790131		n3rm1n	Stove (JOI18_stove)	C++17	50 / 100	1077 ms	3608 KiB

stove

/// note: it's actually stove
#include<bits/stdc++.h>
#define endl '\n'
using namespace std;
const long long MAXN = 1e5 + 10;
void speed()
{
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    cout.tie(NULL);
}
long long n, k, a[MAXN];

void read()
{
    cin >> n >> k;
    for (long long i = 1; i <= n; ++ i)
        cin >> a[i];
}

vector < long long > before(MAXN), dp(MAXN);
long long inf = 1e15+10;
long long q = 0;
void divide(long long l, long long r, long long opt_left, long long opt_right)
{
    if(l > r)return;

    //cout << l << " " << r << endl;
    long long mid = (l + r)/2;
    dp[mid] = inf;
    long long best = inf, best_opt = -1;
    long long cost;
    for (long long cut = opt_left; cut <= min(mid, opt_right); ++ cut)
    {
        cost = before[cut-1] + a[mid] - a[cut] + 1;
       /* if(q == 2)
        {
            cout << "**" << endl;
            cout << l << " " << r << " --> " << mid << endl;
            cout << "cut on " << cut << endl;
            cout << cost << endl;
        }*/
        if(cost < best)
        {
            best = cost;
            best_opt = cut;
        }
    }
    dp[mid] = best;
    //cout << q << " " << mid << " " << best << endl;
    divide(l, mid-1, opt_left, best_opt);
    divide(mid+1, r, best_opt, opt_right);

}
void solve()
{
    dp[0] = 0;
    for (long long i = 1; i <= n; ++ i)
        dp[i] = inf;
    for (long long i = 1; i <= k; ++ i)
    {
        q = i;
        before = dp;
        divide(1, n, 1, n);
    }
    cout << dp[n] << endl;
}
int main()
{
   // speed();

    read();
    solve();
    return 0;
}

• Subtask 1: 20 / 20
• Subtask 2: 30 / 30
• Subtask 3: 0 / 50