coding_challenge_1b.py

def dirReduc(arr):
    directions = {
        "NORTH" : "SOUTH" , 
        "SOUTH" : "NORTH" , 
        "WEST" : "EAST" , 
        "EAST" : "WEST" 
    }
    output = []
    i = 0
    while(i < len(arr)-1):
        move      = arr[i]
        next_move = arr[i+1]
        if (next_move == directions[move]):
            i += 2
        else:
            output.append(move)
            i+=1
    return output

# testing - should return ["WEST"]
dirReduc(["NORTH", "SOUTH", "SOUTH", "EAST", "WEST", "NORTH", "WEST"])
# Doh! ['SOUTH', 'NORTH']