Submission #928681

#	Time	Username	Problem	Language	Result	Execution time	Memory
928681		Regulus	Palindromic Partitions (CEOI17_palindromic)	C++17	100 / 100	190 ms	19604 KiB

palindromic

#include <bits/stdc++.h>
#define IO ios::sync_with_stdio(false);cin.tie(0);
#define debug(x) cerr << #x << " = " << (x) << ' '
#define bug(x) cerr << (x) << ' '
#define endl cerr << '\n'
#define all(v) (v).begin(), (v).end()
#define SZ(v) (ll)(v).size()
#define lowbit(x) (x)&-(x)
#define pb emplace_back
#define F first
#define S second
using namespace std;
using ll = long long;
using pll = pair<ll, ll>;

const int N = 1e6+5;
const int MOD = 19993;
const int MOD2 = 1e9+7;
ll sum[N], p[N];
string s;

int main(void)
{ IO
    int T, n, i;

    cin >> T;
    do {
        cin >> s, n = SZ(s);
        s = " " + s;
        for (i=1; i <= n; ++i)
            sum[i] = (sum[i-1] * MOD % MOD2 + s[i]) % MOD2;
        for (i=1, p[0]=1; i <= n; ++i) p[i] = p[i-1] * MOD % MOD2;

        //for (i=1; i <= n; ++i) bug(sum[i]); endl;
        int ans = 0, L = 1, R = n;
        while (L <= R)
        {
            for (i=0; i < n; ++i)
            {
                ll tmp = (sum[L+i] - (sum[L-1] * p[i+1] % MOD2) + MOD2) % MOD2;
                ll tmp2 = (sum[R] - (sum[R-i-1] * p[i+1] % MOD2) + MOD2) % MOD2;
                //debug(tmp), debug(tmp2), endl;
                if (tmp == tmp2) break;
            }
            if (R-L == i) ++ans;
            else ans += 2;
            //debug(L), debug(R), debug(i), endl;
            L += i + 1, R -= i + 1;
        }

        cout << ans << '\n';
    } while (--T);

    return 0;
}

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