NQueen.py

global N
N = 4
 
def printSolution(board):
    for i in range(N):
        for j in range(N):
            print (board[i][j],end=' ')
        print()
 

def isSafe(board, row, col):
 

    for i in range(col):
        if board[row][i] == 1:
            return False
 
    for i, j in zip(range(row, -1, -1), range(col, -1, -1)):
        if board[i][j] == 1:
            return False
 
    for i, j in zip(range(row, N, 1), range(col, -1, -1)):
        if board[i][j] == 1:
            return False
 
    return True
 
def solveNQUtil(board, col):
   
    if col >= N:
        return True
 
    
    for i in range(N):
 
        if isSafe(board, i, col):
           
            board[i][col] = 1
 
          
            if solveNQUtil(board, col + 1) == True:
                return True
 
            board[i][col] = 0

    return False

def solveNQ():
    board = [ [0, 0, 0, 0],
              [0, 0, 0, 0],
              [0, 0, 0, 0],
              [0, 0, 0, 0]
             ]
 
    if solveNQUtil(board, 0) == False:
        print ("Solution does not exist")
        return False
 
    printSolution(board)
    return True
 

solveNQ()