Submission #791938

#	Time	Username	Problem	Language	Result	Execution time	Memory
791938		trucmai	Feast (NOI19_feast)	C++17	100 / 100	105 ms	8012 KiB

feast

//i_love_aisukiuwu
#include <bits/stdc++.h>
using namespace std;

#ifdef LOCAL
	#include "/home/trucmai/.vim/tools.h"
	#define debug(x...) cerr << "\e[91m"<<__func__<<":"<<__LINE__<<" [" << #x << "] = ["; _print(x); cerr << "\e[39m" << endl;
	#else
	#define debug(x...)
#endif

void open(){
  if(fopen("i.inp","r")){
    freopen("i.inp","r",stdin);
    freopen("o.out","w",stdout);
  }
}

#define ll long long
#define all(a) (a).begin(), (a).end()
#define vi vector<ll>
#define pi pair<ll,ll>
#define pii pair<ll,pair<ll,ll>>
#define fi first
#define se second
#define gcd __gcd
#define mset(a,v) memset(a, v, sizeof(a))
#define endl '\n'
#define spc " "

const int MN1 = 1e6 + 5,MN2 = 2e3 + 5,LOG = 27;
const ll MOD = 1e9 + 7,INF = 1e9;
ll n,k,a[MN1],pf[MN1];

void solve(){
  cin>>n>>k;
  for(ll i = 1;i <= n;++i){
    cin>>a[i];
    pf[i] = pf[i-1] + a[i];
  } 
  ll l = 0,r = 3e14,res = 0;
  auto dp=[&](ll x)->pi{
    pi mx = {0,0},f = {0,0};
    for(ll i = 1;i <= n;++i){
      f = max(f,{mx.fi + pf[i] - x,mx.se - 1}); 
      mx = max(mx,{f.fi - pf[i],f.se});
    }
    f.se *= -1;
    return f;
  };
  while(l <= r){
    ll m = (r+l) >> 1; 
    auto [val,cnt] = dp(m);
    debug(l,r,cnt);
    if(cnt <= k){
      r = m - 1;
      res = val + k*m;
    }
    else l = m + 1;
  }
  cout<<res;
}

signed main(){
  cin.tie(0) -> sync_with_stdio(0);
  open();
  ll t = 1; //cin>>t;
  while(t--) solve(); 
  
  #ifdef LOCAL
    cerr << endl << "Time elapsed: " << 1.0 * clock() / CLOCKS_PER_SEC << " s.\n";
  #endif
}

Compilation message (stderr)

feast.cpp: In function 'void open()':
feast.cpp:14:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   14 |     freopen("i.inp","r",stdin);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~
feast.cpp:15:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   15 |     freopen("o.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