Submission #351264

#	Time	Username	Problem	Language	Result	Execution time	Memory
351264		denkendoemeer	Palindromes (APIO14_palindrome)	C++14	100 / 100	31 ms	39660 KiB

palindrome

#include<bits/stdc++.h>
#define ll long long
using namespace std;
int cnt[300005][30],len[300005],nex[300005],cnt2[300005],u;
char s[300005];
int findnex(int nod,int p)
{
    while(s[p]!=s[p-len[nod]-1])
        nod=nex[nod];
    return nod;
}
int update(int nod,int p)
{
    int aux=s[p]-97;
    nod=findnex(nod,p);
    if (cnt[nod][aux]==0){
        ++u;
        len[u]=len[nod]+2;
        nex[u]=cnt[findnex(nex[nod],p)][aux];
        cnt[nod][aux]=u;
    }
    return cnt[nod][aux];
}
int main()
{
    //freopen(".in","r",stdin);
    //freopen(".out","w",stdout);
    fgets(s,300003,stdin);
    int n=strlen(s)-1;
    len[1]=-1;
    u=1;
    nex[0]=nex[1]=1;
    int cur=1,i;
    for(i=0;i<n;i++)
        cur=update(cur,i),cnt2[cur]++;
    ll ans=0;
    for(i=u;i>=0;i--)
        cnt2[nex[i]]=cnt2[nex[i]]+cnt2[i],ans=max(ans,1LL*cnt2[i]*len[i]);
    printf("%lld\n",ans);
return 0;
}

Compilation message (stderr)

palindrome.cpp: In function 'int main()':
palindrome.cpp:28:10: warning: ignoring return value of 'char* fgets(char*, int, FILE*)', declared with attribute warn_unused_result [-Wunused-result]
   28 |     fgets(s,300003,stdin);
      |     ~~~~~^~~~~~~~~~~~~~~~

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