Submission #1095040

#	Time	Username	Problem	Language	Result	Execution time	Memory
1095040		vjudge1	Palindromic Partitions (CEOI17_palindromic)	C++17	100 / 100	194 ms	20568 KiB

palindromic

#include<bits/stdc++.h>
#define ll long long
#define ii pair < int , int >
#define iii pair < int , ii>
#define iv pair < ii , ii >
#define fi first
#define se second
#define y1 dkjfd
using namespace std;
const int N = 1e6 + 5;
const int mod = 1e9 + 7;
const int base = 310;

int pre[N], pw[N];

int mul(int x, int y)
{
    return 1LL * x * y % mod;
}
int add(int x, int y)
{
    return ((1LL * x + y) % mod + mod) % mod;
}

int get(int l, int r)
{
    return add(pre[r], - mul(pre[l - 1], pw[r - l + 1]));
}

main()
{
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);
    // freopen("wormsort.in" , "r" , stdin);
    // freopen("wormsort.out" , "w" , stdout);

    pw[0] = 1;
    for(int i = 1; i <= 1e6; i++)
        pw[i] = mul(pw[i - 1], base);

    int t; cin >> t;
    while(t--)
    {
        string s; cin >> s;
        int n = s.size();
        s = '#' + s;
        
        for(int i = 1; i <= n; i++)
            pre[i] = add(mul(pre[i - 1], base), s[i]);

        int ans = 0;
        int i = 1;
        int d = 1;
        while(true)
        {
            while(get(i, i + d - 1) != get(n - i - d + 2, n - i + 1)) d++;
            // cout << i << " " << d << endl;
            if(i != n - i - d + 2) ans += 2;
            else ans += 1;
            i += d;
            d = 1;
            if(i > (n + 1) / 2) break;
        }
        cout << ans << '\n';
    }
    
    
}

Compilation message (stderr)

palindromic.cpp:30:1: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type]
   30 | main()
      | ^~~~

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