Submission #1290486

#	Time	Username	Problem	Language	Result	Execution time	Memory
1290486		luvna	Feast (NOI19_feast)	C++20	100 / 100	89 ms	10960 KiB

feast

#include<bits/stdc++.h>

#define MASK(i) (1 << (i))
#define pub push_back
#define all(v) v.begin(), v.end()
#define compact(v) v.erase(unique(all(v)), end(v))
#define pii pair<int,int>
#define fi first
#define se second
#define endl "\n"
#define sz(v) (int)(v).size()
#define dbg(x) "[" #x " = " << (x) << "]"
#define vi vector<int>

using namespace std;
bool START_ALLOC;

template<class T> bool minimize(T& a, T b){if(a > b) return a = b, true;return false;}
template<class T> bool maximize(T& a, T b){if(a < b) return a = b, true;return false;}

typedef long long ll;
typedef long double ld;

mt19937_64 rng(chrono::high_resolution_clock::now().time_since_epoch().count());
ll rand(ll l, ll r){return uniform_int_distribution<ll>(l, r)(rng);}

const int MAX = 3e5 + 15;

int n, k;
int a[MAX];

namespace AlienTrick{
    #define pll pair<ll,ll>

    pll dp[MAX][2];

    pll f(ll penalty){
        dp[0][0] = {0, 0};
        dp[0][1] = {a[0] - penalty, 1};

        for(int i = 1; i < n; i++){
            dp[i][0] = max(dp[i-1][0], dp[i-1][1]);
            dp[i][1] = max(make_pair(dp[i-1][0].fi + a[i] - penalty, dp[i-1][0].se + 1),
                           make_pair(dp[i-1][1].fi + a[i], dp[i-1][1].se));
        }

        return max(dp[n-1][0], dp[n-1][1]);
    }

    ll query(){
        ll lo = 1, hi = 3e15, res = 0;
        int counter = 0;
        while(lo <= hi){
            ll mid = (lo + hi) >> 1;
            if(f(mid).se >= k){
                res = mid;
                lo = mid+1;
            }
            else hi = mid-1;
        }
        return f(res).fi + 1LL*res*k;
    }
}

void solve(){
    cin >> n >> k;

    for(int i = 0; i < n; i++) cin >> a[i];

    cout << AlienTrick::query() << endl;
}

bool END_ALLOC;
signed main(){
    ios_base::sync_with_stdio(NULL);
    cin.tie(0); cout.tie(0);

    #define task "task"

    cerr << "[Static Memory : " << fixed << setprecision(2) << (((&END_ALLOC) - (&START_ALLOC)) / (1024.0 * 1024.0)) << "mb]\n";
    if(fopen(task".INP", "r")){
        freopen(task".INP", "r", stdin);
        freopen(task".OUT", "w", stdout);
    }

    int t; t = 1; //cin >> t;
    while(t--) solve();
}

Compilation message (stderr)

feast.cpp: In function 'int main()':
feast.cpp:82:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   82 |         freopen(task".INP", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
feast.cpp:83:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   83 |         freopen(task".OUT", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~

• 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