제출 #599710

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
599710		Mounir	Boarding Passes (BOI22_passes)	C++14	0 / 100	9 ms	468 KiB

passes

#include <bits/stdc++.h>
#define all(v) v.begin(), v.end()
#define chmax(x, v) x = max(x, v)
#define chmin(x, v) x = min(x, v)
#define pb push_back
#define pii pair<int, int>
#define sz(x) (int)x.size()
#define x first
#define y second
#define int long long
using namespace std;

const int N = 1e5 + 5, G = 10, B = (1 << G);
const int OO = 1e18;
int nAvant[N][G], nApres[N][G];
vector<int> occs[G];
int dp[B];

int nInversions(int n){
      return (n * n - n);
}

signed main(){ 
      string line = ""; cin >> line;
      int nVals = line.length();
      vector<int> vals;
      for (int i = 0; i < nVals; ++i)
            vals.pb(line[i] - 'A');
      
      for (int c = 0; c < G; ++c)
            nAvant[0][c] = 0;
      nAvant[0][vals[0]]++;
      for (int iVal = 1; iVal < nVals; ++iVal){
            for (int val = 0; val < G; ++val)
                  nAvant[iVal][val] = nAvant[iVal - 1][val];
            nAvant[iVal][vals[iVal]]++;
      }

      for (int iVal = 0; iVal < nVals; ++iVal)
            for (int val = 0; val < G; ++val)
                  nApres[iVal][val] = nAvant[nVals - 1][val] - nAvant[iVal][val];

      for (int iVal = 0; iVal < nVals; ++iVal)
            occs[vals[iVal]].pb(iVal);
      for (int mask = 0; mask < B; ++mask)
            dp[mask] = OO;
      dp[0] = 0;

      for (int mask = 0; mask < B; ++mask){
            vector<int> presents;
            for (int i = 0; i < G; ++i){
                  if ((mask&(1 << i)) > 0)
                        presents.pb(i);
            }
         //   cout << dp[mask] << endl;

            for (int c = 0; c < G; ++c){
                  if ((mask&(1 << c)) == 0){
                        int nCur = sz(occs[c]);
                        if (nCur == 0){
                              chmin(dp[mask|(1 << c)], dp[mask]);
                              continue;
                        }
                        vector<int> before, after;
                        for (int iVal : occs[c]){
                              int sum = 0;
                              for (int present : presents)
                                    sum += nAvant[iVal][present];
                              before.pb(sum);
                              sum = 0;
                              for (int present : presents)
                                    sum += nApres[iVal][present];
                              after.pb(sum);
                        }

                        vector<int> prefix(nCur, 0), suffix(nCur, 0);
                        prefix[0] = before[0];
                        for (int i = 1; i < nCur; ++i)
                              prefix[i] = prefix[i - 1] + before[i];
                        suffix[nCur - 1] = after[nCur - 1];
                        for (int i = nCur - 2; i >= 0; --i)
                              suffix[i] = suffix[i + 1] + after[i];

                        int best = OO;
                        for (int coupe = -1; coupe < nCur; ++coupe){
                              int actu = 0;
                              if (coupe >= 0)
                                    actu += 4 * prefix[coupe];
                              if (coupe + 1 < nCur)
                                    actu += 4 * suffix[coupe + 1];
                              actu += nInversions(coupe + 1);
                              actu += nInversions(nCur - coupe - 1);
                              chmin(best, actu);
                        }


                        if (false && mask == 4){
                              cout << "trans " << c << " " << best << endl;
                              for (int iVal : occs[c])
                                    cout << iVal << " ";
                              cout << endl;
                              for (int i : before)
                                    cout << i << " ";
                              cout << endl;
                              for (int i : after)
                                    cout << i << " ";
                              cout << endl;
                              cout << "---" << endl;
                        }

                        chmin(dp[mask|(1 << c)], dp[mask] + best);
                  }
            }
      }
      cout << fixed << setprecision(10) <<  dp[B - 1]/4.0 << endl;
      return 0;   
}

• Subtask 1: 0 / 5
• Subtask 2: 0 / 25
• Subtask 3: 0 / 30
• Subtask 4: 0 / 40