Submission #822311

#	Time	Username	Problem	Language	Result	Execution time	Memory
822311		qqspeed20015	Genetics (BOI18_genetics)	C++14	47 / 100	339 ms	83088 KiB

genetics

#include <bits/stdc++.h>
using namespace std;

int main() {
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    //freopen("input.txt", "r", stdin);
    //freopen("output.txt", "w", stdout);
    map <char, int> hashValue;
    hashValue['A'] = 1; hashValue['B'] = 2; hashValue['C'] = 3; hashValue['D'] = 4;
    int n, m, k;
    cin >> n >> m >> k;
    vector <vector <int>> matrixEncode(n, vector <int> (m));
    vector <long long> weightHash(n);
    vector <vector <long long>> sumOfColumn(m, vector <long long> (5, 0));
    long long totalWeight = 0; // sum (weightHash[i]) for i in 0 -> n - 1
    vector <int> indexMatching;
    for (int i = 0; i < n; i++) {
        string series;
        cin >> series;
        for (int j = 0; j < m; j++)
            matrixEncode[i][j] = hashValue[series[j]];
    }
    
    for (int i = 0; i < n; i++) {
        weightHash[i] = rand();
        totalWeight += weightHash[i];
    }
    
    for (int i = 0; i < n; i++) {
        for (int j = 0; j < m; j++)
            sumOfColumn[j][matrixEncode[i][j]] += weightHash[i];
    }

    for (int i = 0; i < n; i++) {
        long long hashValue1 = 0, hashValue2 = 0;
        // Approach 1: Row view
        hashValue1 = (totalWeight - weightHash[i]) * k;
        
        // Approach 2: Column view
        for (int j = 0; j < m; j++) {
            for (int c = 1; c <= 4; c++) {
                if (matrixEncode[i][j] != c)
                    hashValue2 += sumOfColumn[j][c];
            }
        }
        
        if (hashValue1 == hashValue2)
            indexMatching.push_back(i);
    }
    
    if (indexMatching.empty()) {
        cout << -1;
        return 0;
    }
    
    // Spurious hit --> Checking again
    int x = indexMatching.size();
    for (auto &index: indexMatching) {
        bool checkValid = true;
        for (int i = 0; i < n; i++) {
            if (i == index)
                continue;
            int countDifferent = 0;
            for (int j = 0; j < m; j++)
                countDifferent += (matrixEncode[index][j] != matrixEncode[i][j]);
            checkValid &= (countDifferent == k);
        }
        if (checkValid) {
            cout << (index + 1);
            return 0;
        }
    }
    
    // Miss hit --> Actual fake!
    cout << -1;
    return 0;
}

Compilation message (stderr)

genetics.cpp: In function 'int main()':
genetics.cpp:58:9: warning: unused variable 'x' [-Wunused-variable]
   58 |     int x = indexMatching.size();
      |         ^

• Subtask 1: 0 / 27
• Subtask 2: 19 / 19
• Subtask 3: 28 / 28
• Subtask 4: 0 / 26