هک‌ها و تشعشعات وجدان آزاد

def solution(x, a):
    covered_time = [-1] * x  # Record the time, each position is covered
    uncovered = x  # Record the number of uncovered position
 
    for index in range(len(a)):
        if covered_time[a[index] - 1] != -1:
            # This position is already covered
            continue
        # This position is to be covered
        covered_time[a[index] - 1] = index
        uncovered -= 1
        if uncovered == 0:
            # All positions are covered
            return index
 
    # Finally, some positions are not covered
    return -1