Submission #646988

#	Time	Username	Problem	Language	Result	Execution time	Memory
646988		Saksham_2000	Split the sequence (APIO14_sequence)	C++14	71 / 100	125 ms	131072 KiB

sequence

/*

author: Saksham_2000

"It's a slow process, 
but quitting won't speed it up"

*/



#include <bits/stdc++.h>

using namespace std;



#define ll long long
#define ld long double
#define pll pair<ll,ll>
#define cld complex<ld>
#define vl vector<ll>
#define vvl vector<vector<ll>>
#define vld vector<ld>
#define vvld vector<vector<ld>>
#define vpll vector<pll>
#define vcld vector<cld>
#define ff first
#define ss second
#define pb push_back
#define mp make_pair
#define lb lower_bound
#define ub upper_bound
#define eb emplace_back
#define PI acos(-1)
#define endl "\n"
#define fix(f,n) fixed<<setprecision(n)<<f
#define all(x) x.begin(),x.end()
#define rev(p) reverse(p.begin(),p.end());
#define mset(a,val) memset(a,val,sizeof(a));
#define IOS ios_base::sync_with_stdio(false);cin.tie(NULL);cout.tie(NULL);
#define popcount(x) __builtin_popcountll(x)
#define sz(x) ((ll)x.size())
#define FOR(i,a,b)  for(ll i=a;i<=b;i++)
#define FORR(i,a,b)  for(ll i=a;i>=b;i--)

const ll N = 2e5 + 5;

const ll M = 1000000007;

const ll MM = 998244353;

mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());

#define ordered_set tree<ll,null_type,less<ll>,rb_tree_tag,tree_order_statistics_node_update>

ll begtime = clock();
#define end_routine() cerr << "\n\nTime elapsed: " << (clock() - begtime)*1000/CLOCKS_PER_SEC << " ms\n\n";

void __print(int x) {cerr << x;}
void __print(long x) {cerr << x;}
void __print(long long x) {cerr << x;}
void __print(unsigned x) {cerr << x;}
void __print(unsigned long x) {cerr << x;}
void __print(unsigned long long x) {cerr << x;}
void __print(float x) {cerr << x;}
void __print(double x) {cerr << x;}
void __print(long double x) {cerr << x;}
void __print(char x) {cerr << '\'' << x << '\'';}
void __print(const char *x) {cerr << '\"' << x << '\"';}
void __print(const string &x) {cerr << '\"' << x << '\"';}
void __print(bool x) {cerr << (x ? "true" : "false");}
void __print(const complex<long double> &x) {cerr << '{'; __print(x.real()); cerr << ','; __print(x.imag()); cerr << '}';}

template<typename T, typename V>
void __print(const pair<T, V> &x) {cerr << '{'; __print(x.first); cerr << ','; __print(x.second); cerr << '}';}
template<typename T>
void __print(const T &x) {int f = 0; cerr << '{'; for (auto &i : x) cerr << (f++ ? "," : ""), __print(i); cerr << "}";}
void _print() {cerr << "]\n";}
template <typename T, typename... V>
void _print(T t, V... v) {__print(t); if (sizeof...(v)) cerr << ", "; _print(v...);}
#ifndef ONLINE_JUDGE
#define debug(x...) cerr << "[" << #x << "] = ["; _print(x)
#else
#define debug(x...)
#endif



template<typename T, typename F>
void chmax( T &a, F b) {
  if (b > a)a = b;
}

template<typename T, typename F>
void chmin( T &a, F b) {
  if (b < a)a = b;
}


ll powM(ll a, ll b, ll m)
{
  if (a <= 0)return 0;
  a %= m;

  ll ans = 1LL;
  while (b)
  {
    if (b & 1)ans = ans * a % m;
    //ans = mulmod(ans, a, m);
    a = a * a % m;
    //a = mulmod(a, a, m);
    b >>= 1;
  }

  return ans;
}



ll poww(ll a, ll b)
{
if(b<0)return 0;
  ll ans = 1;
  while (b)
  {
    if (b & 1)ans = ans * a;
    a = a * a;
    b >>= 1;
  }

  return ans;

}



void OJ() {


#ifndef ONLINE_JUDGE

  freopen("input.txt", "r", stdin);
  freopen("output.txt", "w", stdout);

#endif

}

struct seg{ ld x; ll m,b,id;};

vector<seg>hull;

// for maxima, lines 2b inserted in non-dec order, for minima-> non inc.

void insert_to_hull(ll m,ll b,ll id){
  while(hull.size()){
    seg s=hull.back();
    if(s.b+s.m*s.x>b+m*s.x){ // for minima, '<' sign will come.
      if(s.m-m)hull.push_back({(b-s.b)/(ld)(s.m-m),m,b,id});
      return;
    }
    hull.pop_back();
  }
  hull={{LLONG_MIN,m,b,id}}; 
}

pll query_hull(ll x){
  seg s=*--upper_bound(hull.begin(),hull.end(),x,[](ll a,seg b){return a<b.x;});
  return {s.b+s.m*x,s.id};
}

int main() {

  IOS;

//  OJ();

  
ll n;cin>>n;

ll k;cin>>k;


vl pr(n+1);

vvl dp(n+1,vl(k+1,-1e18));

vvl prv(n+1,vl(k+1,-1));

for(ll i=1;i<=n;i++){
  ll x;cin>>x;
  pr[i]=pr[i-1]+x;
}


for(ll i=0;i<=n;i++){
  dp[i][0]=0;
}

for(ll kk=1;kk<=k;kk++){
  hull.clear();
  insert_to_hull(pr[n]+pr[0],-pr[n]*pr[0]+dp[0][kk-1],0);
for(ll i=1;i<=n;i++){
  // dp[j][kk-1] will be used here. (j<i)
  auto val=query_hull(pr[i]);
  dp[i][kk]=val.ff-pr[i]*pr[i],prv[i][kk]=val.ss;
  insert_to_hull(pr[i]+pr[n],-pr[n]*pr[i]+dp[i][kk-1],i);
}
}

ll ans=-1e18,st=-1;

FOR(i,1,n){
  if(ans<dp[i][k]){
    ans=dp[i][k];
    st=i;
  }
}

vl recover;
ll cur=k;
while(cur>0&&st!=-1){
  recover.pb(st);
  st=prv[st][cur--];
}

reverse(recover.begin(),recover.end());

cout<<ans<<endl;


for(auto d:recover){
  cout<<d<<" ";
}



  return 0;


}

Compilation message (stderr)

sequence.cpp: In function 'void OJ()':
sequence.cpp:143:10: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  143 |   freopen("input.txt", "r", stdin);
      |   ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~
sequence.cpp:144:10: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  144 |   freopen("output.txt", "w", stdout);
      |   ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 11 / 11
• Subtask 2: 11 / 11
• Subtask 3: 11 / 11
• Subtask 4: 17 / 17
• Subtask 5: 21 / 21
• Subtask 6: 0 / 29