Submission #388944

#	Time	Username	Problem	Language	Result	Execution time	Memory
388944		phathnv	Palindromes (APIO14_palindrome)	C++11	100 / 100	95 ms	87728 KiB

palindrome

#include <bits/stdc++.h>
using namespace std;

typedef long long ll;

const int N = 3e5 + 7;

struct node{
    int len, cnt;
    node *nxt[26], *suf;
    node(int _len = 0){
        len = _len;
        cnt = 0;
        for(int i = 0; i < 26; i++)
            nxt[i] = nullptr;
        suf = nullptr;
    }
};

string s;
node *root1, *root2, *cur;
vector <node*> a[N];

void insert(int pos){
    int id = s[pos] - 'a';
    if (pos - cur->len - 1 < 0)
        cur = cur->suf;
    while(s[pos] != s[pos - cur->len - 1])
        cur = cur->suf;
    if (cur->nxt[id] != nullptr){
        cur = cur->nxt[id];
        return;
    }
    cur->nxt[id] = new node(cur->len + 2);
    if (cur == root1){
        cur->nxt[id]->suf = root2;
    } else {
        node *tmp = cur->suf;
        while(s[pos] != s[pos - tmp->len - 1])
            tmp = tmp->suf;
        cur->nxt[id]->suf = tmp->nxt[id];
    }
    cur = cur->nxt[id];
}

int main(){
    ios_base::sync_with_stdio(0);
    cin.tie(0);

    cin >> s;

    root1 = new node(-1);
    root2 = new node(0);
    root2->suf = root1;
    cur = root2;
    for(int i = 0; i < (int) s.size(); i++){
        insert(i);
        a[cur->len].push_back(cur);
        cur->cnt++;
    }
    ll res = 0;
    for(int i = s.size(); i >= 1; i--)
        for(node *cur : a[i]){
            res = max(res, (ll) cur->len * cur->cnt);
            cur->suf->cnt += cur->cnt;
            cur->cnt = 0;
        }
    cout << res;
    return 0;
}

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