Submission #1122168

#	Time	Username	Problem	Language	Result	Execution time	Memory
1122168		vjudge1	Boarding Passes (BOI22_passes)	C++17	100 / 100	417 ms	52528 KiB

passes

// Bolatulu
#include <bits/stdc++.h>
// #include <art.h>

/*
#pragma GCC target ("avx2")
#pragma GCC optimization ("O3")
#pragma GCC optimization ("unroll-loops")
*/

typedef long long ll;
typedef unsigned long long ull; 
typedef double db;
#define pb push_back
#define eb emplace_back
#define ins insert
#define F first
#define S second
#define md (tl+tr)/2
#define TL v+v,tl,md
#define TR v+v+1,md+1,tr
#define Tl t[v].l,tl,md
#define Tr t[v].r,md+1,tr
#define all(x) (x).begin(),(x).end()
#define yes cout << "YES\n"
#define no cout << "NO\n"
#define int long long
// #define file(s) freopen(s".in", "r", stdin); freopen(s".out", "w", stdout);
using namespace std;

int binpow(int a,int n,int M) {
    if (n==0)
        return 1;
    if (n%2!=0)
        return (a * binpow(a,n-1,M))%M;
    int z=binpow(a,n/2,M);
    return (z*z)%M;
}

const ll INF = 1e18+7;
const int N = 1e5+7;

string s;
int n,dp[N],g,pref[16][16][N],suf[16][16][N],sz[16],L[N],R[N];
vector <int> d[N],bits[N];

int calc(int x,int mask,int b) {
    int res=0;
    for (auto i : bits[mask]) {
        if (x>=0)
            res+=pref[b][i][x];
        if (x+1<sz[b])
            res+=suf[b][i][x+1];
    }
    return res;
}

void solve() {
    cin >> s;
    n=s.size();
    s=" "+s;
    for (int i=1;i<=n;i++) {
        g=max(g,(int)(s[i]-'A'+1));
        d[s[i]-'A'].pb(i);
    }
    for (int i=0;i<g;i++)
        sz[i]=d[i].size();
    for (int i=0;i<g;i++) {
        for (int j=0;j<g;j++) {
            for (int k=0;k<sz[i];k++) {
                int l=-1,r=sz[j];
                while (l+1<r) {
                    int mid=(l+r)/2;
                    if (d[j][mid]<d[i][k])
                        l=mid;
                    else
                        r=mid;
                }
                if (i!=j)
                    L[k]=(l+1)*2, R[k]=(sz[j]-r)*2;
                else
                    L[k]=k, R[k]=sz[i]-k-1;
                if (k>0)
                    pref[i][j][k]=pref[i][j][k-1];
                pref[i][j][k]+=L[k];
            }
            for (int k=sz[i]-1;k>=0;k--) {
                if (k+1<sz[i])
                    suf[i][j][k]=suf[i][j][k+1];
                suf[i][j][k]+=R[k];
            }
        }
    }
    for (int mask=1;mask<(1<<g);mask++) {
        dp[mask]=INF;
        for (int i=0;i<g;i++) {
            if (mask>>i&1)
                bits[mask].pb(i);
        }
        for (auto i : bits[mask]) {
            int l=-1,r=sz[i]-1;
            while (l+2<r) {
                int m1=l+(r-l)/3, m2=r-(r-l)/3;
                if (calc(m1,mask,i)<=calc(m2,mask,i))
                    r=m2;
                else
                    l=m1;
            }
            int val=INF;
            for (int j=l;j<=r;j++)
                val=min(val,calc(j,mask,i));
            dp[mask]=min(dp[mask],dp[mask^(1<<i)]+val);
        }
    }
    cout << setprecision(1) << fixed << dp[(1<<g)-1]*0.5; 
}   

signed main() {
    // file("jenga");
    ios_base::sync_with_stdio(false);cin.tie(nullptr);cout.tie(nullptr);
    int test = 1;
    // cin >> test;
    while (test--) {
        solve();
        if (test)
            cout << '\n';
    }
    return 0;
}

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