[Lesson 4][Counting Elements] FrogRiverOne

app.codility.com/programmers/lessons/4-counting_elements/frog_river_one/

FrogRiverOne coding task - Learn to Code - Codility

# 1~X 위치가 모두 나타나는 최초 시간

def solution(X, A):
    S = set(range(1, X + 1))
    N = len(A)
    for i in range(N):
        if A[i] in S:
            S.remove(A[i])
            if len(S) == 0:
                return i
    return -1


print(solution(5, [1, 3, 1, 4, 2, 3, 5, 4]))  # 6
print(solution(2, [2, 2, 2, 2, 2]))           # -1