Submission #666521

#	Time	Username	Problem	Language	Result	Execution time	Memory
666521		mychecksedad	Boarding Passes (BOI22_passes)	C++17	55 / 100	2064 ms	1424 KiB

passes

/* Author : Mychecksdead */
#include<bits/stdc++.h>
using namespace std;
#define setp() cout << setprecision(15)
#define all(x) x.begin(), x.end()
const int N = 1e5 + 100;

int n;
string s;
double dp[N];
vector<int> v[15], pref, vis;

void solve(){
    cin >> s; n = s.length();

    for(int i = 0; i < n; ++i) v[s[i]-'A'].push_back(i);

    for(int i = 0; i < (1<<15); ++i) dp[i] = 1e15;

    dp[0] = 0;

    for(int mask = 1; mask < (1<<15); ++mask){
        pref.clear();
        pref.resize(n);
        for(int j = 0; j < 15; ++j){
            if(mask&(1<<j)){
                for(int pos: v[j]) pref[pos] = 1;
            }
        }
        for(int i = 1; i < n; ++i) pref[i] = pref[i - 1] + pref[i];
        for(int j = 0; j < 15; ++j){
            if(mask&(1<<j)){
                double passes = 0;

                long long cur = 0;

                long long s = v[j].size();
                for(int i = 0; i < s; ++i){
                    cur += pref[n - 1] - pref[v[j][i]] - (s-i-1);
                }
                passes = cur + s*(s-1)/4.0;
                for(long long i = 1; i <= s; ++i){
                    cur -= pref[n - 1] - pref[v[j][i - 1]] - (s-(i-1)-1);
                    cur += pref[v[j][i - 1]] - i;
                    long long k1 = s - i;
                    passes = min(passes, cur + (i*(i-1)+k1*(k1-1))/4.0);
                }

                dp[mask] = min(dp[mask], dp[mask^(1<<j)] + passes);
            }
        }
    }


    cout << dp[(1<<15)-1];
}



int main(){
    cin.tie(0); ios::sync_with_stdio(0);
    int T = 1, aa;
    // cin >> T;aa=T;
    setp();
    while(T--){
        // cout << "Case #" << aa-T << ": ";
        solve();
    }
    return 0;
 
}

Compilation message (stderr)

passes.cpp: In function 'int main()':
passes.cpp:62:16: warning: unused variable 'aa' [-Wunused-variable]
   62 |     int T = 1, aa;
      |                ^~

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