Submission #73378

#	Time	Username	Problem	Language	Result	Execution time	Memory
73378		Vardanyan	Palindromes (APIO14_palindrome)	C++14	0 / 100	1086 ms	29828 KiB

palindrome

#pragma GCC optimize "-O3"
#include <bits/stdc++.h>
using namespace std;
const int N = 3000*100+7;
const long long MOD = 1000000007;
long long h1[N],h2[N];
long long p[N];
long long hashcode1(int l,int r){
    return h1[r]-(h1[l-1]*p[r-l+1])%MOD;
}
long long hashcode2(int l,int r){
    return h2[r]-(h2[l-1]*p[r-l+1])%MOD;
}
int main()
{
    string s;
    cin>>s;
    int n = s.length();
    p[0] = 1;
    for(int i = 1;i<=n;i++) p[i] = (p[i-1]*239)%MOD;
    string srev = s;
    reverse(srev.begin(),srev.end());
    for(int i = 1;i<=n;i++){
        h1[i] = (h1[i-1]*239+s[i-1])%MOD;
        h2[i] = (h2[i-1]*239+srev[i-1])%MOD;
    }
    map<long long,int> mp;
    int ans = 0;
    for(int i = 1;i<=n;i++){
        for(int j = i;j<=n;j++){
            int x = hashcode1(i,j);
            int jj = n-i+1;
            int ii = n-j+1;
            int y = hashcode2(ii,jj);
            if(x == y){
                    mp[x]++;
                    ans = max(ans,(j-i+1)*mp[x]);
            }
        }
    }
    cout<<ans<<endl;
    return 0;
}

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