Submission #898153

#	Time	Username	Problem	Language	Result	Execution time	Memory
898153		GrindMachine	Boarding Passes (BOI22_passes)	C++17	60 / 100	2036 ms	2644 KiB

passes

#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>

using namespace std;
using namespace __gnu_pbds;

template<typename T> using Tree = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
typedef long long int ll;
typedef long double ld;
typedef pair<int,int> pii;
typedef pair<ll,ll> pll;

#define fastio ios_base::sync_with_stdio(false); cin.tie(NULL)
#define pb push_back
#define endl '\n'
#define sz(a) (int)a.size()
#define setbits(x) __builtin_popcountll(x)
#define ff first
#define ss second
#define conts continue
#define ceil2(x,y) ((x+y-1)/(y))
#define all(a) a.begin(), a.end()
#define rall(a) a.rbegin(), a.rend()
#define yes cout << "Yes" << endl
#define no cout << "No" << endl

#define rep(i,n) for(int i = 0; i < n; ++i)
#define rep1(i,n) for(int i = 1; i <= n; ++i)
#define rev(i,s,e) for(int i = s; i >= e; --i)
#define trav(i,a) for(auto &i : a)

template<typename T>
void amin(T &a, T b) {
    a = min(a,b);
}

template<typename T>
void amax(T &a, T b) {
    a = max(a,b);
}

#ifdef LOCAL
#include "debug.h"
#else
#define debug(x) 42
#endif

/*



*/

const int MOD = 1e9 + 7;
const int N = 1e5 + 5;
const int inf1 = int(1e9) + 5;
const ll inf2 = ll(1e18) + 5;

void solve(int test_case)
{
    string s; cin >> s;
    ll n = sz(s);
    s = "$" + s;

    ll siz = 0;
    rep1(i,n){
        amax(siz,(ll)s[i]-'A'+1);
    }

    vector<ll> pos[siz];
    rep1(i,n) pos[s[i]-'A'].pb(i);

    vector<ll> dp(1<<siz,inf2);
    dp[0] = 0;

    vector<ll> pref(n+5);

    rep(mask,1<<siz){
        fill(all(pref),0);
        rep(c,siz){
            if(mask&(1<<c)){
                trav(i,pos[c]){
                    pref[i]++;
                }
            }
        }

        rep1(i,n) pref[i] += pref[i-1];

        rep(c,siz){
            if(mask&(1<<c)) conts;
            auto &p = pos[c];
            if(p.empty()){
                amin(dp[mask|(1<<c)],dp[mask]);
                conts;
            }

            ll s1 = 0, s2 = sz(p);
            ll cost1 = 0, cost2 = 0;

            trav(i,p){
                cost2 += pref[n]-pref[i];
            }

            ll mn_cost = inf2;
            amin(mn_cost,s2*(s2-1)+cost2*4);

            trav(i,p){
                s1++, s2--;
                cost1 += pref[i];
                cost2 -= pref[n]-pref[i];
                amin(mn_cost,s1*(s1-1)+s2*(s2-1)+cost1*4+cost2*4);
            }

            amin(dp[mask|(1<<c)],dp[mask]+mn_cost);
        }
    }

    ld ans = (ld)dp[(1<<siz)-1]/4;
    cout << fixed << setprecision(11);
    cout << ans << endl;
}

int main()
{
    fastio;

    int t = 1;
    // cin >> t;

    rep1(i, t) {
        solve(i);
    }

    return 0;
}

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