Submission #119390

#	Time	Username	Problem	Language	Result	Execution time	Memory
119390		zubec	Palindromic Partitions (CEOI17_palindromic)	C++14	100 / 100	155 ms	28960 KiB

palindromic

#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef long double ld;

const int N = 1000100;

const ll MOD = 1e9+9;

string s;

int n;

ll hsh[N], st[N];

ll gethsh(int l, int r){
    return (hsh[r]-hsh[l-1]+MOD)*st[n-r]%MOD;
}

void solve(){
    st[0] = 1;
    cin >> s;
    n = s.size();
    s = '#' + s;
    for (int i = 1; i <= n; i++){
        st[i] = (st[i-1] * 43) % MOD;
        hsh[i] = (hsh[i-1] + st[i]*s[i])%MOD;
    }
    int i = 1;
    int j = n;
    int sz = 1;
    int ans = 0;
    while(1){
        if (i+sz-1 >= j-sz+1){
            ++ans;
            break;
        }
        if (gethsh(i, i+sz-1) == gethsh(j-sz+1, j)){
            ans += 2;
            i += sz;
            j -= sz;
            sz = 1;
            if (i-1 == j)
                break;
            continue;
        }
        ++sz;
    }
    cout << ans << "\n";
}

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

    int tt;
    cin >> tt;
    while(tt--){
        solve();
    }

}

/**

1
deleted

*/

• Subtask 1: 15 / 15
• Subtask 2: 20 / 20
• Subtask 3: 25 / 25
• Subtask 4: 40 / 40