Submission #584260

#	Time	Username	Problem	Language	Result	Execution time	Memory
584260		talant117408	Necklace (Subtask 1-3) (BOI19_necklace1)	C++17	85 / 85	363 ms	71036 KiB

necklace

#include <bits/stdc++.h>
 
using namespace std;
 
typedef long long ll;
typedef pair <int, int> pii;
typedef pair <ll, ll> pll;
 
#define pb                  push_back
#define mp                  make_pair
#define all(v)              (v).begin(),(v).end()
#define rall(v)             (v).rbegin(),(v).rend()
#define lb                  lower_bound
#define ub                  upper_bound
#define sz(v)               int((v).size())
#define do_not_disturb      ios::sync_with_stdio(0);cin.tie(0);cout.tie(0);
#define endl                '\n'

vector <int> z_function(string s) {
    int n = sz(s);
    vector <int> z(n);
    for (int i = 1, l = 0, r = 0; i < n; i++) {
        if (i <= r)
            z[i] = min (r - i + 1, z[i - l]);
        while (i + z[i] < n && s[z[i]] == s[i + z[i]])
            z[i]++;
        if (i + z[i] - 1 > r)
            l = i, r = i + z[i] - 1;
    }
    return z;
}

void solve() {
    string s, t;
    cin >> s >> t;
    int ans = 0, inds = -1, indt = -1;
    vector <vector <int>> Z(sz(s), vector <int> (sz(t))), reversed_Z(sz(s), vector <int> (sz(t)));
    
    string q = s;
    for (int i = 0; i < sz(s); i++) {
        string tmp = q + '$' + t;
        auto res = z_function(tmp);
        for (int j = sz(s) + 1; j < sz(s) + sz(t) + 1; j++) 
            Z[i][j - sz(s) - 1] = res[j];
        rotate(q.begin(), q.begin() + 1, q.end());
        q.back() = '#';
    }
    for (int i = 0; i < sz(s); i++) {
        for (int j = 0; j < sz(t); j++) {
            auto r = (j + Z[i][j]) % sz(t);
            if (j + Z[i][j] < sz(t))
                reversed_Z[i][r] = max(reversed_Z[i][r], Z[i][j]);
        }
    }
    for (int i = 0; i < sz(s); i++) {
        for (int j = 0; j < sz(t); j++) {
            if (Z[i][j] == 0) continue;
            int nxt = (i + Z[i][j]) % sz(s);
            if (Z[i][j] + reversed_Z[nxt][j] > ans && Z[i][j] + reversed_Z[nxt][j] <= sz(s)) {
                ans = Z[i][j] + reversed_Z[nxt][j];
                inds = i; indt = (j - reversed_Z[nxt][j] + sz(t)) % sz(t);
                //~ indt = sz(t) - (indt + ans - 1) - 1;
            }
        }
    }
    
    q = s;
    reverse(all(t));
    for (int i = 0; i < sz(s); i++) {
        fill(all(reversed_Z[i]), 0);
        string tmp = q + '$' + t;
        auto res = z_function(tmp);
        for (int j = sz(s) + 1; j < sz(s) + sz(t) + 1; j++) 
            Z[i][j - sz(s) - 1] = res[j];
        rotate(q.begin(), q.begin() + 1, q.end());
        q.back() = '#';
    }
    for (int i = 0; i < sz(s); i++) {
        for (int j = 0; j < sz(t); j++) {
            auto r = (j + Z[i][j]) % sz(t);
            if (j + Z[i][j] < sz(t))
                reversed_Z[i][r] = max(reversed_Z[i][r], Z[i][j]);
        }
    }
    for (int i = 0; i < sz(s); i++) {
        for (int j = 0; j < sz(t); j++) {
            if (Z[i][j] == 0) continue;
            int nxt = (i + Z[i][j]) % sz(s);
            if (Z[i][j] + reversed_Z[nxt][j] > ans && Z[i][j] + reversed_Z[nxt][j] <= sz(s)) {
                ans = Z[i][j] + reversed_Z[nxt][j];
                inds = i; indt = (j - reversed_Z[nxt][j] + sz(t)) % sz(t);
                indt = sz(t) - (indt + ans - 1) - 1;
            }
        }
    }
    
    cout << ans << endl;
    cout << inds << ' ' << indt << endl;
}

int main() {
    do_not_disturb
    
    int t = 1;
    //~ cin >> t;
    while (t--) {
        solve();
    }
    
    return 0;
}

• Subtask 1: 25 / 25
• Subtask 2: 20 / 20
• Subtask 3: 40 / 40