main.py

#!/usr/bin/python

def print_sudoku(list_sud):
    for i in range(9):
        if i%3==0:
            print '-----------------------\n',
        for j in range(9):
            if j%3==0:
                print '|',
            print list_sud[i][j],
        print

    print '-----------------------\n'



def find_empty_location(list_sud):
    for row in range(9):
        for col in range(9):
            if (list_sud[row][col] == 0):
                return (row, col)
    return (None, None)


# Returns a boolean which indicates whether any assigned entry
# in the specified row matches the given number.
def used_in_row(list_sud, row, num):
    for i in range(9):
        if (list_sud[row][i] == num):
            return True
    return False


# Returns a boolean which indicates whether any assigned entry
# in the specified column matches the given number.
def used_in_col(list_sud, col, num):
    for i in range(9):
        if (list_sud[i][col] == num):
            return True
    return False


# Returns a boolean which indicates whether any assigned entry
# within the specified 3x3 box matches the given number
def used_in_box(list_sud, row, col, num):
    for i in range(3):
        for j in range(3):
            if (list_sud[i + row][j + col] == num):
                return True
    return False


# Checks whether it will be legal to assign num to the given row,col
# Returns a boolean which indicates whether it will be legal to assign
# num to the given row,col location.
def check_location_is_safe(list_sud, row, col, num):
    # Check if 'num' is not already placed in current row,
    # current column and current 3x3 box
    return not used_in_row(list_sud, row, num) \
        and not used_in_col(list_sud, col, num)\
	and not used_in_box(list_sud, row - row % 3, col - col % 3, num)


def solve_sudoku(list_sud):
    # If there is no unassigned location, we are done
    (row, col) = find_empty_location(list_sud)
    if row == None:
        return True

    # consider digits 1 to 9
    for num in range(1, 10):

        # if looks promising
        if (check_location_is_safe(list_sud, row, col, num)):

            # make tentative assignment
            list_sud[row][col] = num

            # return, if sucess, ya!
            if (solve_sudoku(list_sud)):
                return True

            # failure, unmake & try again
            list_sud[row][col] = 0

    # this triggers backtracking
    return False


# Driver main function to test above functions
if __name__ == "__main__":


    with open('evenMoreConsistent.txt','rb') as fp:
        lines=fp.readlines()
        data_dict = {}
        count=0
        temp_data = []
        for line in lines:
            if 'easy' in line or 'medium' in line or 'hard' in line  or 'evil' in line:
                data_dict[count]=temp_data
                count+=1
                temp_data=[]
                continue
            else:
                if line!='\n':
                    temp_data += [map(int,list(line[:-1]))]




    del data_dict[0]

    for key in [1,2,3,4]:
        print key,solve_sudoku(data_dict[key])
        print_sudoku(data_dict[key])