Submission #460597

#	Time	Username	Problem	Language	Result	Execution time	Memory
460597		prvocislo	Palindromes (APIO14_palindrome)	C++17	100 / 100	26 ms	35028 KiB

palindrome

#include <iostream>
#include <vector>
#include <algorithm>
#include <set>
typedef long long ll;
using namespace std;

const int maxn = 3e5 + 5, abc = 26;
//const int maxn = 15, abc = 26;
struct node
{
    int nx[abc], len, link, cnt; // hrany dopredu, dlzka, spatna hrana, pocet kratov kedy som videla tento palindrom
} vr[maxn];
string s;
int suf, nd = 2;
void add(int i, int ch)
{
    while (i - vr[suf].len - 1 < 0 || s[i - vr[suf].len - 1] != s[i])
    {
        suf = vr[suf].link;
    }
    if (vr[suf].nx[ch])
    {
        suf = vr[suf].nx[ch];
        vr[suf].cnt++;
        return;
    }
    nd++;
    vr[nd].len = vr[suf].len + 2;
    vr[suf].nx[ch] = nd;
    int j = vr[suf].link;
    suf = nd;
    vr[suf].cnt++;
    if (vr[suf].len == 1)
    {
        vr[suf].link = 2;
        return;
    }
    while (i - vr[j].len - 1 < 0 || s[i - vr[j].len - 1] != s[i])
    {
        j = vr[j].link;
    }
    vr[suf].link = vr[j].nx[ch];
}
int main()
{
    ios::sync_with_stdio(false);
    cin.tie(0);
    vr[1].link = 1, vr[1].len = -1;
    vr[2].link = 1, vr[2].len = 0;
    suf = 2;
    cin >> s;
    int n = s.size();
    for (int i = 0; i < n; i++)
        add(i, s[i] - 'a');
    ll ans = 0;
    for (int i = nd; i > 0; i--)
    {
        //cout << vr[i].cnt << "*" << vr[i].len << "\n";
        ans = max(ans, vr[i].cnt * 1ll * vr[i].len);
        vr[vr[i].link].cnt += vr[i].cnt;
    }
    cout << ans << "\n";
    return 0;
}

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