Submission #654601

#	Time	Username	Problem	Language	Result	Execution time	Memory
654601		Lobo	Boarding Passes (BOI22_passes)	C++17	55 / 100	199 ms	160972 KiB

passes

#include<bits/stdc++.h>
using namespace std;
const long long inf = (long long) 1e18 + 10;
const int inf1 = (int) 1e9 + 10;
#define int long long
#define dbl long double
#define endl '\n'
#define sc second
#define fr first
#define mp make_pair
#define pb push_back
#define all(x) x.begin(), x.end()

const int maxn = 1e4+10;
const int maxg = 11;

int n, a[maxn];
dbl pf[(1<<maxg)][maxn], dp[(1<<maxg)];
vector<int> pos[maxg];

void solve() {
    string s; cin >> s;
    n = s.size();
    vector<char> cc;
    for(auto x : s) cc.pb(x);
    sort(all(cc));
    cc.erase(unique(all(cc)),cc.end());
    for(int i = 1; i <= n; i++) {
        a[i] = lower_bound(all(cc),s[i-1])-cc.begin();
        pos[a[i]].pb(i);
    }
    int g = cc.size();
    if(g == 1) {
        dbl ans = 0;
        for(int i = 1; i <= n; i++) ans+= min((dbl) (i-1)/2,(dbl) (n-i)/2);
        cout.setf(ios::fixed);
        cout.precision(10);
        cout << ans << endl;
        return;
    }

    for(int mask = 1; mask < (1<<g); mask++) {
        pf[mask][0] = 0;
        for(int i = 1; i <= n; i++) {
            pf[mask][i] = pf[mask][i-1];
            if((1<<a[i])&mask) pf[mask][i]++;
        }

        dp[mask] = inf;
        for(int i = 0; i < g; i++) {
            if(((1<<i)&mask) == 0) continue;
            int mask1 = mask-(1<<i);
            dbl ans1 = dp[mask1];
            int sz = pos[i].size();
            for(int j = 1; j <= pos[i].size(); j++) {
                int x = pos[i][j-1];
                ans1+= min(pf[mask1][x]+((dbl) j-1)/2, pf[mask1][n]-pf[mask1][x]+((dbl) sz-j)/2);
                // cout << " " << min(pf[mask1][x]+((dbl) j-1)/2, pf[mask1][n]-pf[mask1][x]+((dbl) pos[i].size()-j)/2) << endl;
            }
            dp[mask] = min(dp[mask],ans1);
            // cout << mask << " " << i << " = " << ans1 << " " << pf[mask1][1] << endl;
        }
    }
    cout.setf(ios::fixed);
    cout.precision(10);
    cout << dp[(1<<g)-1] << endl;
}

int32_t main() {
    ios::sync_with_stdio(false); cin.tie(0);

    // freopen("in.in", "r", stdin);
    // freopen("out.out", "w", stdout);
    int tt = 1;
    // cin >> tt;
    while(tt--) {
        solve();
    }

}

Compilation message (stderr)

passes.cpp: In function 'void solve()':
passes.cpp:55:30: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::vector<long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   55 |             for(int j = 1; j <= pos[i].size(); j++) {
      |                            ~~^~~~~~~~~~~~~~~~

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