Submission #1140697

#	Time	Username	Problem	Language	Result	Execution time	Memory
1140697		12345678	Palindromes (APIO14_palindrome)	C++20	0 / 100	0 ms	328 KiB

palindrome

#include <bits/stdc++.h>

using namespace std;

struct node
{
    int cnt, sz;
    node *nxt[26], *suf;
    node(int c, int s)
    {
        cnt=c;
        sz=s;
        for (int i=0; i<26; i++) nxt[i]=0;
    }
};
typedef node* pnode;
pnode rt=new node(0, -1), srt=new node(0, 0), t=rt;

int n;
long long ans;
string s;

void dfs(pnode x)
{
    for (int i=0; i<26; i++) if (x->nxt[i]) dfs(x->nxt[i]);
    ans=max(ans, (long long)x->cnt*x->sz);
    x->suf->cnt+=x->cnt;
    //cout<<"exit "<<x->sz<<' '<<x->cnt<<'\n';
}

int main()
{
    cin.tie(NULL)->sync_with_stdio(false);
    rt->suf=rt;
    srt->suf=rt;
    cin>>s;
    n=s.size();
    for (int i=0; i<n; i++)
    {
        //cout<<i<<'\n';
        while (1)
        {
            //cout<<"debug "<<i<<" "<<t->sz<<'\n';
            if (i-1-t->sz>=0&&s[i-1-t->sz]==s[i]) break;
            t=t->suf;
        }
        //cout<<"here\n";
        if (t->nxt[s[i]-'a'])
        {
            t=t->nxt[s[i]];
            t->cnt++;
            continue;
        }
        auto nw=new node(1, t->sz+2);
        t->nxt[s[i]-'a']=nw;
        if (nw->sz==1)
        {
            nw->suf=srt;
            t=nw;
            continue;
        }
        while (1)
        {
            t=t->suf;
            if (i-1-t->sz>=0&&s[i-1-t->sz]==s[i])
            {
                nw->suf=t->nxt[s[i]-'a'];
                break;
            }
        }
        t=nw;
    }
    dfs(rt);
    dfs(srt);
    cout<<ans;
}

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