Queen's Attack II Discussions | Algorithms | HackerRank
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Queen's Attack II

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  • mohammed_abrar_1
     + 0 comments

    //JAVA15: import java.io.; import java.util.; import java.util.stream.*;

    class Result {

    public static int queensAttack(int n, int k, int r_q, int c_q, List<List<Integer>> obstacles) {
    Set<String> obstacleSet = new HashSet<>();
    for (List<Integer> obs : obstacles) {
        obstacleSet.add(obs.get(0) + "-" + obs.get(1));
    }

    int[][] directions = {
        {-1, 0}, {1, 0}, {0, -1}, {0, 1},   // vertical and horizontal
        {-1, -1}, {-1, 1}, {1, -1}, {1, 1}  // diagonals
    };

    int attackableSquares = 0;

    for (int[] dir : directions) {
        int r = r_q + dir[0];
        int c = c_q + dir[1];

        while (r >= 1 && r <= n && c >= 1 && c <= n && !obstacleSet.contains(r + "-" + c)) {
            attackableSquares++;
            r += dir[0];
            c += dir[1];
        }
    }

    return attackableSquares;
}

    }

    public class Solution { public static void main(String[] args) throws IOException { BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(System.in)); BufferedWriter bufferedWriter = new BufferedWriter(new FileWriter(System.getenv("OUTPUT_PATH")));

        String[] firstMultipleInput = bufferedReader.readLine().replaceAll("\\s+$", "").split(" ");
    int n = Integer.parseInt(firstMultipleInput[0]);
    int k = Integer.parseInt(firstMultipleInput[1]);

    String[] secondMultipleInput = bufferedReader.readLine().replaceAll("\\s+$", "").split(" ");
    int r_q = Integer.parseInt(secondMultipleInput[0]);
    int c_q = Integer.parseInt(secondMultipleInput[1]);

    List<List<Integer>> obstacles = new ArrayList<>();

    IntStream.range(0, k).forEach(i -> {
        try {
            obstacles.add(
                Stream.of(bufferedReader.readLine().replaceAll("\\s+$", "").split(" "))
                    .map(Integer::parseInt)
                    .collect(Collectors.toList())
            );
        } catch (IOException ex) {
            throw new RuntimeException(ex);
        }
    });

    int result = Result.queensAttack(n, k, r_q, c_q, obstacles);

    bufferedWriter.write(String.valueOf(result));
    bufferedWriter.newLine();

    bufferedReader.close();
    bufferedWriter.close();
}

    }

  • kami518
     + 0 comments

    Given plenty of time, I can complete medium diffcult level problem. but I cannot complate in half an hour.

  • quote_unquote
     + 0 comments
    /*
 * Complete the 'queensAttack' function below.
 *
 * The function is expected to return an INTEGER.
 * The function accepts following parameters:
 *  1. INTEGER n
 *  2. INTEGER k
 *  3. INTEGER r_q
 *  4. INTEGER c_q
 *  5. 2D_INTEGER_ARRAY obstacles
 */

void _info(int n, int k, int r_q, int c_q, vector<vector<int>> obstacles) {
    cout << "n: " << n << endl;
    cout << "q: " << r_q << "," << c_q << endl;
    for (auto ob: obstacles) {
        auto r = ob[0];
        auto c = ob[1];
        cout << "o: " << r << ',' << c << endl;
    }    
}

int _north(int n, int r_q, int c_q, const vector<vector<int>>& obstacles) {
    vector<int> z = { r_q };
    for (auto ob: obstacles) {
        if (ob[1] == c_q) {
            auto dr = r_q - ob[0];
            if (dr > 0) { z.push_back(dr); }
        }
    }
    auto d = *min_element(z.begin(), z.end());
    return d - 1;
}

int _east(int n, int r_q, int c_q, const vector<vector<int>>& obstacles) {
    vector<int> z = { n + 1 - c_q };
    for (auto ob: obstacles) {
        if (ob[0] == r_q) {
            auto dc = ob[1] - c_q;
            if (dc > 0) { z.push_back(dc); }
        }
    }
    auto d = *min_element(z.begin(), z.end());
    return d - 1;
}

int _south(int n, int r_q, int c_q, const vector<vector<int>>& obstacles) {
    vector<int> z = { n + 1 - r_q };
    for (auto ob: obstacles) {
        if (ob[1] == c_q) {
            auto dr = ob[0] - r_q;
            if (dr > 0) { z.push_back(dr); }
        }
    }
    auto d = *min_element(z.begin(), z.end());
    return d - 1;
}

int _west(int n, int r_q, int c_q, const vector<vector<int>>& obstacles) {
    vector<int> z = { c_q };
    for (auto ob: obstacles) {
        if (ob[0] == r_q) {
            auto dc = c_q - ob[1];
            if (dc > 0) { z.push_back(dc); }
        }
    }
    auto d = *min_element(z.begin(), z.end());
    return d - 1;
}

int _ne(int n, int r_q, int c_q, const vector<vector<int>>& obstacles) {
    int k = min(r_q, n + 1 - c_q);
    vector<int> z = {k};
    for (auto ob: obstacles) {
        auto dr = r_q - ob[0];
        auto dc = ob[1] - c_q;
        if ((dr > 0) && (dr == dc)) { z.push_back(dr); }
    }
    auto d = *min_element(z.begin(), z.end());
    return d - 1;
}

int _se(int n, int r_q, int c_q, const vector<vector<int>>& obstacles) {
    int k = min(n + 1 - r_q, n + 1 - c_q);
    vector<int> z = {k};
    for (auto ob: obstacles) {
        auto dr = ob[0] - r_q;
        auto dc = ob[1] - c_q;
        if ((dr > 0) && (dr == dc)) { z.push_back(dr); }
    }
    auto d = *min_element(z.begin(), z.end());
    return d - 1;
}

int _sw(int n, int r_q, int c_q, const vector<vector<int>>& obstacles) {
    int k = min(n + 1 - r_q, c_q);
    vector<int> z = {k};
    for (auto ob: obstacles) {
        auto dr = ob[0] - r_q;
        auto dc = c_q - ob[1];
        if ((dr > 0) && (dr == dc)) { z.push_back(dr); }
    }
    auto d = *min_element(z.begin(), z.end());
    return d - 1;
}

int _nw(int n, int r_q, int c_q, const vector<vector<int>>& obstacles) {
    int k = min(r_q, c_q);
    vector<int> z = {k};
    for (auto ob: obstacles) {
        auto dr = r_q - ob[0];
        auto dc = c_q - ob[1];
        if ((dr > 0) && (dr == dc)) { z.push_back(dr); }
    }
    auto d = *min_element(z.begin(), z.end());
    return d - 1;
}

int queensAttack(int n, int k, int r_q, int c_q, vector<vector<int>> obstacles) {
    
    // _info(n, k, r_q, c_q, obstacles);
    
    int cnt = 0;
    cnt += _north(n, r_q, c_q, obstacles);
    cnt += _east(n, r_q, c_q, obstacles);
    cnt += _south(n, r_q, c_q, obstacles);
    cnt += _west(n, r_q, c_q, obstacles);
    cnt += _ne(n, r_q, c_q, obstacles);
    cnt += _se(n, r_q, c_q, obstacles);
    cnt += _sw(n, r_q, c_q, obstacles);
    cnt += _nw(n, r_q, c_q, obstacles);
    
    // cout << cnt << endl;
    return cnt;
}

  • yashdeora98294
     + 0 comments

    Here is problem solution in Python, Java, C++, C and Javascript - https://programmingoneonone.com/hackerrank-queens-attack-ii-problem-solution.html

  • 2301641720004_A
     + 0 comments

    **simple python solution **

    >

    def queensAttack(n, k, r_q, c_q, obstacles):

    attacks = 0
directions = [(1, 0),(-1, 0),(0, 1),(0, -1),(1, 1),(-1, 1),(1, -1), (-1, -1) ]

obstacles = set(map(tuple, obstacles))

for dr, dc in directions:
    r, c = r_q, c_q
    while True:
        r += dr
        c += dc
        if not (1 <= r <= n and 1 <= c <= n): 
            break
        if (r, c) in obstacles:
            break
        attacks += 1

return attacks