coding_challenge_solution.py

# All credit to the following users on Code Wars:
# aenik97, CSNqwer, kickh, joei26, suhlob
opposite = {'NORTH': 'SOUTH', 'EAST': 'WEST', 'SOUTH': 'NORTH', 'WEST': 'EAST'}

def dirReduc(plan):
    new_plan = []
    for d in plan:
        if new_plan and new_plan[-1] == opposite[d]:
            new_plan.pop()
        else:
            new_plan.append(d)
    return new_plan