nQueensGrading.py

# CPSC460/560 AI
# Python program to grade n-queens solution

import pandas as pd
import sys


def printBoard(board, N):
    for i in range(N):
        for j in range(N-1):
            print(board[i][j], ", ", end='')
        print(board[i][N-1])


# check if a queen at [row][col] is attacked. We need to check only left for queen's safety.
def isSafe(board, row, col, N):
    # Check this row on left side
    for i in range(col):
        if board[row][i] == 1:
            return False
    # Check upper diagonal on left
    for i, j in zip(range(row-1, -1, -1), range(col-1, -1, -1)):
        if board[i][j] == 1:
            return False
    # Check lower diagonal on left
    for i, j in zip(range(row+1, N, 1), range(col-1, -1, -1)):
        if board[i][j] == 1:
            return False
    return True


# checking if the solution is valid
def isValid(board, N):
    for row in range(N):
        Qs = 0
        for col in range(N):
            if board[row][col] == 1:
                Qs += 1
                if not isSafe(board, row, col, N):
                    return False
        if Qs != 1:  # making sure there is a queen per row
            print("Queens on row ", row, " invalid.")
            return False
    return True


def main():
    # input filename and solution filename are passed via commandline
    inputf, solutionf, = sys.argv[1:]

    # checking if solution is valid
    df = pd.read_csv(inputf, header=None)
    df2 = pd.read_csv(solutionf, header=None)
    board2 = df2.values.tolist()  # make it a list
    printBoard(board2, len(board2))
    if not isValid(board2, len(board2)):
        print("xxxxx solution is ..... invalid xxxxxxxxxxxxx")
    else:
        print("solution is ..... valid")

    print(".......................................................")
    # checking if initial condition met
    df_df2_mul = df.mul(df2)
    if df_df2_mul.sum().sum() == 1:
        print("Yes, initial condition is satisfied!")
    else:
        print("NO, initial condition is NOT satisfied!")


if __name__ == '__main__':
    main()