Submission #866324

#	Time	Username	Problem	Language	Result	Execution time	Memory
866324		nikuradze	Necklace (Subtask 1-3) (BOI19_necklace1)	C++14	0 / 85	43 ms	436 KiB

necklace

/*
Я русский,
     Я иду до конца.
     Я русский,
     Моя кровь от Отца.

     Я русский,
     И мне повезло.
     Я русский,
     Всему миру назло.

     Я русский!
*/
//#pragma GCC optimize("O3")'
#pragma GCC optimize("Ofast")
#pragma GCC optimize("O3,unroll-loops")
#pragma GCC target("avx2,bmi,bmi2,lzcnt,popcnt")
#include <cstdio>
#include <cmath>
#include <set>
#include <vector>
#include <iostream>
#include <algorithm>
#include <map>
using namespace std;
#define double long double
#define int long long
using ll = long long;
const int mod = 1e9 + 7;
const int mod9 = 1e9 + 9;
const ll MAXN = 1e6 + 100;
const int MAXB = 8;
const int MAXL = 1e6 + 1e5;
#ifndef ONLINE_JUDGE
#define debug(x) cerr << (#x) << ": " << x << endl;
#else
#define debug(x)
#endif
int bin_pow(int x, int e) {
    int c = x, r = 1;
    for (; e; e >>= 1, c = c * 1LL * c % mod) {
        if (e & 1) r = r * 1LL * c % mod;
    }
    return r;
}
int rev(int a) {
    return bin_pow(a, mod - 2);
}
int make_add(int x, int y) {
    if ((ll)x + y >= mod) return x + y - mod;
    return x + y;
}
int mul(int x, int y) {
    ll p = (ll(x)) * y;
    return p % mod;
}
int gcd(int a, int b) {
    while (a > 0 && b > 0) {
        int c = a;
        a = b % a;
        b = c;
    }
    return a + b;
}
vector<int> prefix_function(string s) {
    int n = (int)s.length();
    vector<int> pi(n);
    for (int i = 1; i < n; ++i) {
        int j = pi[i - 1];
        while (j > 0 && s[i] != s[j])
            j = pi[j - 1];
        if (s[i] == s[j])  ++j;
        pi[i] = j;
    }
    return pi;
}
int get(string s, string t) {
    if (s.size() > t.size()) swap(s, t);
    int n = s.size(), m = t.size();
    s = s + s;
    t = t + t;
    int ans = 0;
    for (int i = 0; i < n; i++) {
        for (int j = 0; j < m; j++) {
            string to_ab;
            for (int p = i; p < i + n; p++) to_ab += s[p];
            to_ab += '#';
            for (int p = j; p < j + m; p++) to_ab += t[p];
            vector<int> ab = prefix_function(to_ab);
            //for (auto c : ab) cout << c << " ";
            //cout << endl;
            string to_ba = to_ab;
            reverse(to_ba.begin(), to_ba.end());
            vector<int> ba = prefix_function(to_ba);
           // for (auto c : ba) cout << c << " ";
         //   cout << endl;
            for (int p = n + 1; p <= n + m; p++) {
                int cur_add = ab[p];
                if (cur_add != p - n) continue;               
                int pos = n + m + 1 - cur_add - 1;
                int may = ba[pos];
                ans = max(ans, may + cur_add);
            }
        }
    }
    return ans;
}
void solve() {
    string s, t;
    cin >> s >> t;
    int mx1 = get(s, t);
    reverse(t.begin(), t.end());
    int mx2 = get(s, t);
    cout << max(mx1, mx2);
}
signed main() {
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);
    int t = 1 - 1 + 1;
    // cin >> t;
    while (t--) {
        solve();
    }
}
/*
abcd
dcab
*/

• Subtask 1: 0 / 25
• Subtask 2: 0 / 20
• Subtask 3: 0 / 40