Submission #635319

#	Time	Username	Problem	Language	Result	Execution time	Memory
635319		tvladm2009	Palindromes (APIO14_palindrome)	C++14	0 / 100	26 ms	36336 KiB

palindrome

#include <iostream>

using namespace std;

const int MAX_N = 3 * 1e5;
const int SIGMA = 26;
string s;

struct Node {
    int next[SIGMA];
    int sufflink;
    int len;
    int num;
    int occ = 0;
};

Node tree[MAX_N + 3];
int cnt = 2, suffix = 2;

void addletter(int pos) {
    int let = s[pos] - 'a';
    int cur = suffix, curlen = 0;
    while (true) {
        curlen = tree[cur].len;
        if (pos - curlen - 1 >= 0 && s[pos - curlen - 1] == s[pos]) {
            break;
        }
        cur = tree[cur].sufflink;
    }
    if (tree[cur].next[let]) {
        suffix = tree[cur].next[let];
        return;
    }
    cnt++;
    suffix = cnt;
    tree[cnt].len = tree[cur].len + 2;
    tree[cur].next[let] = cnt;
    if (tree[cnt].len == 1) {
        tree[cnt].sufflink = 2;
        tree[cnt].num = 1;
        return;
    }
    while (true) {
        cur = tree[cur].sufflink;
        curlen = tree[cur].len;
        if (pos - curlen - 1 >= 0 && s[pos - curlen - 1] == s[pos]) {
            tree[cnt].sufflink = tree[cur].next[let];
            break;
        }
    }
    tree[cnt].num = tree[tree[cnt].sufflink].num + 1;
}

void init() {
    tree[1].len = -1;
    tree[1].sufflink = 1;
    tree[2].len = 0;
    tree[2].sufflink = 1;
}

int main() {
    cin >> s;
    int n = s.size();
    init();
    for (int i = 0; i < n; i++) {
        addletter(i);
    }
    int answer = 0;
    for (int i = cnt; i >= 1; i--) {
        tree[i].occ++;
        answer = max(answer, tree[i].occ * tree[i].len);
        tree[tree[i].sufflink].occ += tree[i].occ;
    }
    cout << answer;
    return 0;
}

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