Question

Can you explain how this code for the 8 Queens Problem works? It's in C++

In case you dont know what the 8 Queens problem is, "The eight queens puzzle is the problem of placing eightchess queens on an 8×8 chessboard so that no two queensthreaten each other; thus, a solution requires that no two queens share the same row, column, or diagonal."

This is the code:

#include <iostream>

#include <cmath>

using namespace std;

bool ok(int q[], int c) {

    for (int i = 0; i < c; i++){

    if (q[i] == q[c] || abs(q[i] - q[c]) == c - i)

    return false;

    }

    return true;

}

void print(int q[]) {

    static int numSolutions = 0;

    cout << "Solution #" << ++numSolutions << ": ";

    for (int i = 0; i < 8; i++)

        cout << q[i];

    cout << "\n";

}

int main() {

    int q[8] = {0};

    int c = 0;

    while (c >= 0) {

    if (c == 7) {

    print(q);

    c--;

    }

    else q[++c] = -1;

    while (c >= 0) {

     q[c]++;

    if (q[c] == 8)

    c--;

    else if (ok(q, c))

        break;

    }

    }

return 0;

}

Answer 1

The Eight Queen Puzzle 2

mean, That

nition

huple 1

lse else ok (1,1 ok 0 fahe

Last modified. 16.55