Submission #250653

#	Time	Username	Problem	Language	Result	Execution time	Memory
250653		Sorting	Palindromic Partitions (CEOI17_palindromic)	C++14	100 / 100	254 ms	26388 KiB

palindromic

#include <bits/stdc++.h>

using namespace std;

typedef long long ll;

const int k_N = 1e6 + 3;
const int cnt_Mod = 1;
const array<ll, cnt_Mod> k_Mod{(int)1e9 + 7}, k_Base{293};

int dp[k_N];
string s;
int n;

array<ll, cnt_Mod> h[k_N], b_pow[k_N];

ll get_hash(int l, int r, int idx){
    if(l == 0) return h[r][idx];
    ll ans = (h[r][idx] - h[l - 1][idx] * b_pow[r - l + 1][idx]) % k_Mod[idx];
    return (ans < 0) ? (ans + k_Mod[idx]) : ans;
}

bool equal(int l1, int r1, int l2, int r2){
    for(int i = 0; i < cnt_Mod; ++i)
        if(get_hash(l1, r1, i) != get_hash(l2, r2, i))
            return false;
    return true;
}

void init_hashing(){
    for(int i = 0; i < n; ++i){
        for(int j = 0; j < cnt_Mod; ++j){
            if(i == 0)
                h[i][j] = s[i];
            else
                h[i][j] = (h[i - 1][j] * k_Base[j] + s[i]) % k_Mod[j];
        }
    }

    for(int i = 0; i < n; ++i){
        for(int j = 0; j < cnt_Mod; ++j){
            if(i == 0)
                b_pow[i][j] = 1;
            else
                b_pow[i][j] = b_pow[i - 1][j] * k_Base[j] % k_Mod[j];
        }
    }
}

void solve(){
    cin >> s;
    n = (int)s.size();

    if(n == 1){
        cout << "1\n";
        return;
    }


    init_hashing();

    int mid = (n - 1) / 2, mid2 = (n - 2) / 2;
    int ans = 0, i = 0;
    while(true){
        if(i > mid)
            break;

        bool changed = false;
        for(int j = i; j <= mid2; ++j){
            //if(j >= n - j - 1) break;

            if(equal(i, j, n - j - 1, n - i - 1)){
                ans += 2;
                i = j + 1;
                changed = true;
                break;
            }
        }
        if(!changed){
            ans++;
            break;
        }
    }

    cout << ans << "\n";
}

int main(){
    ios::sync_with_stdio(false);
    cin.tie(NULL);

    int t;
    cin >> t;

    while(t--)
        solve();
}

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