A solution to 8 queen problem in python3

8queen-solver

import itertools
def valid(solution):
    col_1 = 0
    for row_1 in solution:
        row_1 = int(row_1)
        col_2 = 0
        for row_2 in solution:
            row_2 = int(row_2)
            if col_1 != col_2: # do not compare to itself
                if col_1 == col_2: # same column? not gonna happend, but I want to leave it here as a guide
                    return False
                if row_1 == row_2: # same row
                    return False
                if abs(row_1 - row_2) == abs(col_1 - col_2): # same diagonal
                    return False
            col_2 += 1
        col_1 += 1
    return True
#a putative solution is saved as an 8-array where the n-th element is the row and n is the column
#for example the first permutation 01234567 will have queens in the main diagonal of the board
#we use permutation as we don't want duplicated rows (columns won't be duplicated because the position is the col)
solutions = itertools.permutations('01234567')
count = 0
count_solutions = 0
for solution in solutions:
    solution = list(solution)
    if valid(solution):
        count_solutions += 1
        #print(solution) # you want to see the solutions?
    count += 1
print("I've tried %i times and found %i solutions"  % (count, count_solutions))

#outputs: I've tried 40320 times and found 92 solutions