NQueen

nqeeun.py

def is_under_attack(nq_arr,y,x):
    for i in range(y):
        #print(nq_arr,i,y,x)
        if(nq_arr[i] == x):
            return True
        if( abs(y - i) == abs (x - nq_arr[i]) ):
            return True
    return False

def draw_board(nq_arr):
    dim = len(nq_arr)

    for y in range(dim):
        print("|",end="")
        for x in range(dim):
            if( nq_arr[y] == x ):
                print(" Q |",end="")
            else: print("   |",end="")
        print()
        print("-"*(4**2 + 1))
    print()
    
def nqueen_solver(nq_arr,y,x):
    dim = len(nq_arr) -1

    if(y < 0):
        print("Found all solutions")
        return
    #print(nq_arr,y,x)
    if(y > dim):
        print("F",nq_arr)
        draw_board(nq_arr)
        nqueen_solver(nq_arr,y-1, nq_arr[y-1]+1 )
    elif( x <= dim and y <= dim):
        if( is_under_attack(nq_arr,y,x) == False ):
            nq_arr[y] = x;
            nqueen_solver(nq_arr,y+1,0)
        else:
            nqueen_solver(nq_arr,y,x+1)
    else:
        nqueen_solver(nq_arr,y-1, nq_arr[y-1]+1 )

            
            
nq_arr = [None,None,None,None]
nqueen_solver(nq_arr,0,0)