Submission #542034

#	Time	Username	Problem	Language	Result	Execution time	Memory
542034		FatihSolak	Palindromes (APIO14_palindrome)	C++17	0 / 100	26 ms	34648 KiB

palindrome

#include <bits/stdc++.h>
#define N 300005
#define K 30
using namespace std;
const int base = 31;
const int mod = 1e9 + 7;
const int base2 = 41;
const int mod2 = 1e9 + 21;
int cnt[N][K];
int val[N];
long long pre[N];
long long pw[N];
long long pre2[N];
long long pw2[N];
vector<int> palindromes[N];
void solve(){
    string s;
    cin >> s;
    int n = s.size();
    s = "." + s;
    for(int i=1;i<=n;i++){
        pre[i] = (pre[i-1] * base + (s[i] - 'a'))%mod;
        pre2[i] = (pre2[i-1] * base2 + (s[i] - 'a'))%mod2;
    }
    long long ans = 0;
    map<pair<int,int>,int> mp;
    for(int i = n;i>=1;i--){
        if(i == n || s[i+1] != s[i]){
            val[i] = 1;
        }
        else val[i] = val[i+1] + 1;
        palindromes[i].push_back(i + val[i] - 1);
        cnt[val[i]][s[i] - 'a']++;
        for(auto u:palindromes[i+1]){
            if(u + 1 <= n && s[u+1] == s[i] && u + 1 > i + val[i] - 1){
                palindromes[i].push_back(u+1);
            }
        }
        assert(palindromes[i].size() <= 100);
        /*
        for(auto u:palindromes[i]){
            ans = max(ans,1ll*(u-i + 1) * (++mp[{(pre[u] - pw[(u-i + 1)] * pre[i-1] % mod + mod)%mod,(pre2[u] - pw2[(u-i + 1)] * pre2[i-1] % mod2 + mod2)%mod2}]));
        }*/
    }
    for(int i=n;i>=1;i--){
        for(int c = 0;c<K;c++){
            cnt[i][c] += cnt[i+1][c];
            ans = max(ans,1ll*i*cnt[i][c]);
        }
    }
    cout << ans;
}

int32_t main(){
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);
    #ifdef Local
    freopen("in.txt","r",stdin);
    freopen("out.txt","w",stdout);
    #endif
    pw[0] = 1;
    pw2[0] = 1;
    for(int i = 1;i<N;i++){
        pw[i] = pw[i-1] * base % mod;
        pw2[i] = pw2[i-1] * base2 % mod2;
    }
    int t=1;
    //cin>>t;
    while(t--){
        solve();
    }
    #ifdef Local
    cout<<endl<<fixed<<setprecision(2)<<1000.0 * clock() / CLOCKS_PER_SEC<< " milliseconds ";
    #endif
}

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