Submission #1268626

#	Time	Username	Problem	Language	Result	Execution time	Memory
1268626		ducdev	Genetics (BOI18_genetics)	C++17	100 / 100	206 ms	30768 KiB

genetics

// Author: 4uckd3v - Nguyen Cao Duc
#include <bits/stdc++.h>
using namespace std;

#define all(x) (x).begin(), (x).end()

typedef long long ll;

const int MAX_N = 4100;
const int MOD = 1e9 + 7;

int m, n, k;
char a[MAX_N + 5][MAX_N + 5];

int diff(int i, int j) {
    int cnt = 0;
    for (int k = 1; k <= n; k++)
        if (a[i][k] != a[j][k]) cnt++;
    return cnt;
};

namespace SUBTASK_1 {
    const int LIM = 100;

    void Solve() {
        for (int i = 1; i <= m; i++) {
            bool real = true;
            for (int j = 1; j <= m; j++) {
                if (i == j) continue;
                if (diff(i, j) != k) {
                    real = false;
                    break;
                };
            };
            if (real) {
                cout << i << '\n';
                break;
            };
        };
    };
};  // namespace SUBTASK_1

namespace SUBTASK_23 {
    const int M = MAX_N;
    const int N = MAX_N;

    int canReal[M + 5];
    int cache[M + 5][M + 5];
    bitset<N> bs[M];

    bool checkSubtask() {
        for (int i = 1; i <= m; i++)
            for (int j = 1; j <= n; j++)
                if (a[i][j] != 'A' && a[i][j] != 'C') return false;
        return true;
    };

    void Solve() {
        for (int i = 1; i <= m; i++) {
            for (int j = 1; j <= n; j++) {
                bs[i - 1].set(j - 1, a[i][j] == 'A');
            };
        };

        memset(cache, -1, sizeof cache);
        for (int i = 0; i <= m; i++) canReal[i] = true;

        for (int i = 0; i < m; i++) {
            if (!canReal[i]) continue;

            for (int j = 0; j < m; j++) {
                if (i == j) continue;

                if (cache[i][j] == -1) cache[i][j] = cache[j][i] = (bs[i] ^ bs[j]).count();

                if (cache[i][j] != k) {
                    canReal[i] = canReal[j] = false;
                    break;
                };
            };

            if (canReal[i]) {
                cout << i + 1 << '\n';
                break;
            };
        };
    };

};  // namespace SUBTASK_23

namespace SUBTASK_4 {
    const int M = MAX_N;
    const int N = MAX_N;

    int id[256];
    ll hashVal[M + 5], sumCol[N + 5][4];
    mt19937_64 rng(chrono::steady_clock::now().time_since_epoch().count());

    bool verify(int candidate) {
        for (int i = 1; i <= m; i++) {
            if (i == candidate) continue;
            if (diff(candidate, i) != k) return false;
        };
        return true;
    };

    void Solve() {
        id['A'] = 0;
        id['T'] = 1;
        id['G'] = 2;
        id['C'] = 3;

        bool trial = true;
        while (trial) {
            for (int i = 1; i <= m; i++) hashVal[i] = rng() ^ rng();
            for (int i = 1; i <= n; i++)
                for (int j = 0; j < 4; j++) sumCol[i][j] = 0;

            ll sumHash = 0;
            for (int i = 1; i <= m; i++) {
                for (int j = 1; j <= n; j++) {
                    sumCol[j][id[a[i][j]]] += hashVal[i];
                };
                sumHash += hashVal[i];
            };

            for (int i = 1; i <= m; i++) {
                ll sumMatch = 0;
                for (int j = 1; j <= n; j++) sumMatch += sumCol[j][id[a[i][j]]] - hashVal[i];

                if (sumMatch == (sumHash - hashVal[i]) * (n - k)) {
                    if (verify(i)) {
                        cout << i << '\n';
                        trial = false;
                        break;
                    };
                };
            };
        };
    };
};  // namespace SUBTASK_4

int main() {
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    if (fopen("MAIN.INP", "r")) {
        freopen("MAIN.INP", "r", stdin);
        freopen("MAIN.OUT", "w", stdout);
    };

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

    // SUBTASK_1::Solve();
    // SUBTASK_23::Solve();
    SUBTASK_4::Solve();
};

Compilation message (stderr)

genetics.cpp: In function 'int main()':
genetics.cpp:147:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  147 |         freopen("MAIN.INP", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
genetics.cpp:148:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  148 |         freopen("MAIN.OUT", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 27 / 27
• Subtask 2: 19 / 19
• Subtask 3: 28 / 28
• Subtask 4: 26 / 26