Submission #1135307

#	Time	Username	Problem	Language	Result	Execution time	Memory
1135307		mnbvcxz123	Sateliti (COCI20_satellti)	C++20	110 / 110	513 ms	36764 KiB

Main

#include <bits/stdc++.h>
using namespace std;
using ll = long long;
#define f first
#define s second

const int N = 2e3 + 7, base1 = 311, base2 = 10007, MOD = 1e9 + 7;

int n, m;
ll pw[N], pw2[N], h[N][N];
char a[N][N];

void prepare() {
    pw[0] = pw2[0] = 1;
    for (int i = 1; i <= 2 * n; i++) pw[i] = pw[i - 1] * base1 % MOD;
    for (int i = 1; i <= 2 * m; i++) pw2[i] = pw2[i - 1] * base2 % MOD;
    for (int i = 1; i <= 2 * n; i++){
        for (int j = 1; j <= 2 * m; j++) {
            h[i][j] = (h[i - 1][j] * base1 % MOD + h[i][j - 1] * base2 % MOD) % MOD;
            (h[i][j] -= h[i - 1][j - 1] * base1 * base2 % MOD + a[i][j] - 'a' + 1) %= MOD;
        }
    }
}

int get(int a, int b, int x, int y) {
    ll ret = (h[x][y] - h[a - 1][y] * pw[x - a + 1] % MOD - h[x][b - 1] * pw2[y - b + 1] + 1ll * MOD * MOD) % MOD;
    (ret += h[a - 1][b - 1] * pw[x - a + 1] % MOD * pw2[y - b + 1] % MOD + 1ll * MOD * MOD) %= MOD;
    return ret;
}

signed main() {
    cin >> n >> m;
    for (int i = 1; i <= n; i++) {
        for (int j = 1; j <= m; j++) {
            cin >> a[i][j];
            a[i][j + m] = a[i][j];
            a[i + n][j] = a[i][j];
            a[i + n][j + m] = a[i][j];
        }
    } 
    prepare();

    pair<int, int> pos = {1, 1};
    for (int i = 1; i <= n; i++)
        for (int j = 1; j <= m; j++) {
            int l = 1, r = n, ans = -1, ans1 = -1;
            while (l <= r) {
                int mid = l + r >> 1;
                if (get(i, j, i + mid - 1, j + m - 1) == get(pos.f, pos.s, pos.f + mid - 1, pos.s + m - 1)) l = mid + 1;
                else ans = mid, r = mid - 1;
            }
            if (ans == -1) continue;

            l = 1, r = m;
            while (l <= r) {
                int mid = l + r >> 1;
                if (get(i, j, i + ans - 1, j + mid - 1) == get(pos.f, pos.s, pos.f + ans - 1, pos.s + mid - 1)) l = mid + 1;
                else ans1 = mid, r = mid - 1;
            }

            if (ans1 == -1) continue;
            if (a[i + ans - 1][j + ans1 - 1] < a[pos.f + ans - 1][pos.s + ans1 - 1]) pos = {i, j};
        }

    for (int i = pos.f; i < pos.f + n; i++) {
        for (int j = pos.s; j < pos.s + m; j++)
            cout << a[i][j];
        cout << '\n';
    }
}

• Subtask 1: 10 / 10
• Subtask 2: 40 / 40
• Subtask 3: 60 / 60