Algorithms/NQueen.cpp at master · Tanyaverma3114/Algorithms · GitHub

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
#include <iostream>
using namespace std;
bool canPlace(int board[][20], int n, int x, int y)
{
    for (int k = 0; k < x; k++)
    {
        if (board[k][y] == 1)
            return false;
    }
    int i = x;
    int j = y;
    while (i >= 0 && j >= 0)
    {
        if (board[i][j] == 1)
            return false;
        i--;
        j--;
    }
    i = x;
    j = y;
    while (i >= 0 && j < n)
    {
        if (board[i][j] == 1)
            return false;
        i--;
        j++;
    }
    return true;
}
void printBoard(int board[][20], int n)
{
    for (int i = 0; i < n; i++)
    {
        for (int j = 0; j < n; j++)
        {
            cout << board[i][j] << " ";
        }
        cout << endl;
    }
    cout << endl;
}
int solveNQueen(int board[][20], int n, int i)
{
    if (i == n)
    {
        printBoard(board, n);
        return 1;
    }
    int ways = 0;
    for (int j = 0; j < n; j++)
    {
        if (canPlace(board, n, i, j))
        {
            board[i][j] = 1;
            ways += solveNQueen(board, n, i + 1);
            board[i][j] = 0;
        }
    }
    return ways;
}
int main()
{
    int board[20][20] = {0};
    int n, i;
    cin >> n;
    solveNQueen(board, n, 0);
    return 0;
}