Submission #930172

#	Time	Username	Problem	Language	Result	Execution time	Memory
930172		ASN49K	Feast (NOI19_feast)	C++14	100 / 100	89 ms	5736 KiB

feast

#include <bits/stdc++.h>

using namespace std;
#define pb push_back
#define all(x) x.begin(),x.end()
#define int long long
const int inf=1e12;
using i64=long long;
int n;
vector<int>a;
pair<int64_t, int64_t> dp(int64_t lambda)
{
    int64_t mu = 0, nu = 0, p = 0, cnt = 0, _cnt = 0;
    for (size_t i = 0; i < n; ++i)
    {
        p += a[i];
        if (mu + p - lambda > nu)
            nu = mu + p - lambda, _cnt = cnt + 1;
        if (nu - p > mu)
            cnt = _cnt, mu = nu - p;
    }
    return {nu, _cnt};
}
main()
{
    ios::sync_with_stdio(false);
    cin.tie(0);
    int k;
    cin>>n>>k;
    a.resize(n);
    for(int i=0;i<n;i++)
    {
        cin>>a[i];
    }
    int st=0,dr=inf;
    i64 rez=-1e18;
    while(st<=dr)
    {
        int m=(st+dr)/2;
        auto xd=dp(m);
        if(xd.second <= k)
        {
            dr=m-1;
            rez=xd.first+1LL*k*m;
        }
        else
        {
            st=m+1;
        }
    }
    cout<<rez;
    return 0;
}
/*#include <bits/stdc++.h>
using namespace std;

constexpr size_t N = 300000;

int64_t a[N];

pair<int64_t, int64_t> dp(size_t n, int64_t lambda)
{
    int64_t mu = 0, nu = 0, p = 0, cnt = 0, _cnt = 0;
    for (size_t i = 0; i < n; ++i)
    {
        p += a[i];
        if (mu + p - lambda > nu)
            nu = mu + p - lambda, _cnt = cnt + 1;
        if (nu - p > mu)
            cnt = _cnt, mu = nu - p;
    }
    return {nu, _cnt};
}

int main()
{
    ios_base::sync_with_stdio(0);
    cin.tie(0);

    size_t n, k;
    cin >> n >> k;
    for (size_t i = 0; i < n; ++i)
        cin >> a[i];

    int64_t u = 0, v = 1LL << 55;
    while (u < v)
    {
        if (dp(n, (u + v) / 2).second <= k)
            v = (u + v) / 2;
        else
            u = (u + v) / 2 + 1;
    }
    //auto const [objective_val, cnt] = dp(n, u);
    cout << dp(n,u).first + k * u << '\n';
}*/

Compilation message (stderr)

feast.cpp: In function 'std::pair<long int, long int> dp(int64_t)':
feast.cpp:14:26: warning: comparison of integer expressions of different signedness: 'size_t' {aka 'long unsigned int'} and 'long long int' [-Wsign-compare]
   14 |     for (size_t i = 0; i < n; ++i)
      |                        ~~^~~
feast.cpp: At global scope:
feast.cpp:24:1: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type]
   24 | main()
      | ^~~~

• 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: 29 / 29