Submission #1017423

#	Time	Username	Problem	Language	Result	Execution time	Memory
1017423		concac	Feast (NOI19_feast)	C++17	100 / 100	140 ms	15456 KiB

feast

#include <bits/stdc++.h>
#define PI acos(-1.0)
#define pll pair<ll, ll>
#define ll long long
#define ld long double
#define endl "\n"
#define pb push_back
#define ff first
#define ss second
#define ins insert
#define pll2 pair<pll,ll>
#define bit(i,k) ((k>>i)&1)
#define pii pair<int,int>
#define mp make_pair

using namespace std;
const long long mod = 1e9+7;
const ll inf = 1e18;
const ll maxN = 3e5+5;
ll n,k;
ll a[maxN];
pll go(ll lambda){
  pll dp[n+5][2]={};//lay i hoac deo

  dp[0][1].ff=-inf;
  for(int i=1;i<=n;i++){
    dp[i][0]=max(dp[i-1][0],dp[i-1][1]);
    pll p1={dp[i-1][0].ff+a[i]-lambda,dp[i-1][0].ss+1};
    pll p2={dp[i-1][1].ff+a[i],dp[i-1][1].ss};
    dp[i][1]=max(p1,p2);
  }

  return max(dp[n][1],dp[n][0]);
}
void solve() {
  cin>>n>>k;
  for(int i=1;i<=n;i++){
    cin>>a[i];
  }
  ll l=0,r=inf;
  ll lmd;
  ll ans=-inf;
  while(l<r){
    ll md=(l+r+1)/2;
    pll p=go(md);
  
    if(p.ss>=k){ans=p.ff;l=md;}
    else{r=md-1;}
  }
  
  cout<<max(0ll,go(l).ff+k*l);


}
signed main() {
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);
    //  freopen("rao.inp", "r", stdin);
    // freopen("rao.out", "w", stdout);
    ll nhim = 1;
    // cin >> nhim;
    // cout<<nhim<<'\n';
    while (nhim--) {
        solve();
    }
}

Compilation message (stderr)

feast.cpp: In function 'void solve()':
feast.cpp:42:6: warning: unused variable 'lmd' [-Wunused-variable]
   42 |   ll lmd;
      |      ^~~
feast.cpp:43:6: warning: variable 'ans' set but not used [-Wunused-but-set-variable]
   43 |   ll ans=-inf;
      |      ^~~

• 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