Submission #23257

#	Time	Username	Problem	Language	Result	Execution time	Memory
23257		Nurlykhan	Palindromes (APIO14_palindrome)	C++14	23 / 100	153 ms	131072 KiB

palindrome

#include <bits/stdc++.h>

#define pii pair<int, int>
#define f first
#define s second
#define pb push_back
#define mp make_pair
#define ll long long 
#define ld long double
#define sz(v) int(v.size())
#define all(v) v.begin(), v.end()

using namespace std;

const int N = (int) 1000;
const int M = (int) 2e6 + 10;
const ll LINF = (ll) 1e18;
const int INF = (int) 1e9 + 7;
const double EPS = (double) 1e-9;
string st;
ll ans;
int lcp[N];

void solve_odd() {
    vector<string> v;
    for (int i = 0; i < sz(st); i++) {
        int j = 0;
        while (i - j >= 0 && i + j < sz(st) && st[i - j] == st[i + j]) j++;
        v.pb(st.substr(i, j));
    }
    sort(all(v));
    //for (auto it : v) cout << it << endl; cout << "-----\n";
    for (int i = 0; i + 1 < sz(v); i++) {
        lcp[i] = 0;
        while (lcp[i] < min(sz(v[i]), sz(v[i + 1])) && v[i][lcp[i]] == v[i + 1][lcp[i]]) lcp[i]++;
    }
    for (int i = 0; i < sz(v); i++) {
        int mn = lcp[i];
        ans = max(ans, 2ll * sz(v[i]) - 1);
        for (int j = i; j + 1 < sz(v); j++) {
            mn = min(mn, lcp[j]);
            ans = max(ans, (j - i + 2) * 1ll * (mn * 2 - 1));
        }
    }
}


void solve_even() {
    vector<string> v;
    for (int i = 0; i < sz(st); i++) {
        int j = 0;
        while (i - 1 - j >= 0 && i + j < sz(st) && st[i - 1 - j] == st[i + j]) j++;
        v.pb(st.substr(i, j));
    }
    sort(all(v));
    //for (auto it : v) cout << it << endl; cout << "-----\n";
    for (int i = 0; i + 1 < sz(v); i++) {
        lcp[i] = 0;
        while (lcp[i] < min(sz(v[i]), sz(v[i + 1])) && v[i][lcp[i]] == v[i + 1][lcp[i]]) lcp[i]++;
    }
    for (int i = 0; i < sz(v); i++) {
        int mn = lcp[i];
        ans = max(ans, 2ll * sz(v[i]));
        for (int j = i; j + 1 < sz(v); j++) {
            mn = min(mn, lcp[j]);
            ans = max(ans, (j - i + 2) * 2ll * mn);
        }
    }
}

int main() {
    #define fn "balls"
    #ifdef witch
        freopen("input.txt", "r", stdin);
        freopen("output.txt", "w", stdout);
    #else
//        freopen(fn".in", "r", stdin);
//        freopen(fn".out", "w", stdout);
    #endif
    cin >> st;
    solve_odd();
    solve_even();
    cout << ans;
    return 0;
}

• Subtask 1: 8 / 8
• Subtask 2: 15 / 15
• Subtask 3: 0 / 24
• Subtask 4: 0 / 26
• Subtask 5: 0 / 27