Submission #1074847

#	Time	Username	Problem	Language	Result	Execution time	Memory
1074847		huutuan	Uplifting Excursion (BOI22_vault)	C++14	100 / 100	2448 ms	13364 KiB

vault

#pragma GCC optimize("Ofast,unroll-loops")
#pragma GCC target("avx2")
#include <bits/stdc++.h>

using namespace std;

using ll=long long;
// #define int long long

const int M=310;
const ll inf=3e18;
int m;
ll L, a[M*2];

void impossible(){
   cout << "impossible\n";
   exit(0);
}

pair<pair<ll, ll>, vector<ll>> dp(ll power2, pair<pair<ll, ll>, vector<ll>> start, vector<pair<ll, ll>> v){
   ll tl=start.first.first, tr=start.first.second;
   vector<ll> f=start.second;
   ll szl=max(0ll, min(m*m*2ll, (tl-(-inf))/power2));
   ll szr=max(0ll, min(m*m*2ll, (inf-tr)/power2));
   tl-=szl*power2, tr+=szr*power2;
   reverse(f.begin(), f.end());
   f.resize((int)f.size()+szl, -1);
   reverse(f.begin(), f.end());
   f.resize((int)f.size()+szr, -1);
   for (auto &i:v){
      ll val=i.first, cnt=i.second;
      if (val>0){
         for (int j=(int)f.size()-1; j>=val; --j){
            if (f[j-val]!=-1) f[j]=max(f[j], f[j-val]+cnt);
         }
      }else{
         for (int j=0; j-val<(int)f.size(); ++j){
            if (f[j-val]!=-1) f[j]=max(f[j], f[j-val]+cnt);
         }
      }
   }
   reverse(f.begin(), f.end());
   while (f.size() && f.back()==-1){
      tl+=power2;
      f.pop_back();
   }
   reverse(f.begin(), f.end());
   while (f.size() && f.back()==-1){
      tr-=power2;
      f.pop_back();
   }
   if (f.empty()) impossible();
   return {{tl, tr}, f};
}

vector<pair<ll, ll>> v[50];

int32_t main(){
   ios_base::sync_with_stdio(false);
   cin.tie(nullptr);
   cin >> m >> L;
   for (int i=-m; i<=m; ++i) cin >> a[m+i];
   for (int i=-m; i<=m; ++i) if (i){
      ll val=i, cnt=0;
      while (val%2==0) val/=2, ++cnt;
      for (int j=0; j<50; ++j) if (a[m+i]>=(1ll<<j)) v[j+cnt].emplace_back(val, 1ll<<j), a[m+i]-=1ll<<j;
      for (int j=0; j<50; ++j) if (a[m+i]>>j&1) v[j+cnt].emplace_back(val, 1ll<<j);
   }
   pair<pair<ll, ll>, vector<ll>> f={{0, 0}, {a[m]}};
   for (int i=0; i<50; ++i){
      f=dp(1ll<<i, f, v[i]);
      if (abs(f.first.first-L)>>i&1){
         f.first.first+=1ll<<i;
         if (f.second.empty()) impossible();
         f.second.erase(f.second.begin());
      }
      if (abs(f.first.second-L)>>i&1){
         f.first.second-=1ll<<i;
         if (f.second.empty()) impossible();
         f.second.pop_back();
      }
      vector<ll> tmp;
      for (int j=0; j<(int)f.second.size(); j+=2) tmp.push_back(f.second[j]);
      tmp.swap(f.second);
   }
   if (f.first.first>L || f.first.second<L) impossible();
   cout << f.second[(L-f.first.first)>>50] << '\n';
   return 0;
}

• Subtask 1: 5 / 5
• Subtask 2: 15 / 15
• Subtask 3-1: 10 / 10
• Subtask 3-2: 10 / 10
• Subtask 4-1: 10 / 10
• Subtask 4-2: 10 / 10
• Subtask 5-1: 10 / 10
• Subtask 5-2: 10 / 10
• Subtask 6-1: 10 / 10
• Subtask 6-2: 10 / 10