Submission #30167

#	Time	Username	Problem	Language	Result	Execution time	Memory
30167		Andrei1998	Palindromes (APIO14_palindrome)	C++14	100 / 100	109 ms	92700 KiB

palindrome

#include <bits/stdc++.h>

using namespace std;

const int NMAX = 2 * 300000 + 5;

inline int toInt(char ch) {
    if (ch == '#')
        return 0;
    else
        return ch - 'a' + 1;
}

string str;

int nodes;
int alf[NMAX][27];
int h[NMAX];
int father[NMAX];

int ext[NMAX];
int whichNode[NMAX];
int cnt[NMAX];

long long int ans = 1;
void dfs(int node, int realH) {
    for (int i = 0; i < 27; ++ i)
        if (alf[node][i]) {
            dfs(alf[node][i], realH + (i > 0) * (1 + (node > 1)));
            cnt[node] += cnt[alf[node][i]];
        }
    ans = max(ans, 1LL * realH * cnt[node]);
}

int main()
{
    //freopen("data.in", "r", stdin);
    ios_base :: sync_with_stdio(false);

    cin >> str;
    string str2 = "#";
    for (auto it: str) {
        str2 += it;
        str2 += '#';
    }
    str = str2;
    str = " " + str;
    int N = str.size() - 1;

    ++ nodes;

    int center = 0;
    for (int i = 1; i <= N; ++ i) {
        int node = 1;
        int l = 0;

        if (center + ext[center] - 1 >= i) {
            node = whichNode[2 * center - i];
            l = h[node];

            while (l > center + ext[center] - i) {
                node = father[node];
                l --;
            }
        }

        while (i - l >= 1 && i + l <= N && str[i - l] == str[i + l]) {
            if (!alf[node][toInt(str[i - l])]) {
                alf[node][toInt(str[i - l])] = ++ nodes;
                h[nodes] = 1 + h[node];
                father[nodes] = node;
            }

            node = alf[node][toInt(str[i - l])];
            ++ l;
        }
        ext[i] = l;
        whichNode[i] = node;
        ++ cnt[node];

        if (i + ext[i] > center + ext[center])
            center = i;
    }

    dfs(1, 0);

    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