codility MaxCounter

• 문제
  You are given N counters, initially set to 0, and you have two possible operations on them:

increase(X) − counter X is increased by 1,
max counter − all counters are set to the maximum value of any counter.
A non-empty array A of M integers is given. This array represents consecutive operations:

if A[K] = X, such that 1 ≤ X ≤ N, then operation K is increase(X),
if A[K] = N + 1 then operation K is max counter.
For example, given integer N = 5 and array A such that:

A[0] = 3
A[1] = 4
A[2] = 4
A[3] = 6
A[4] = 1
A[5] = 4
A[6] = 4

the values of the counters after each consecutive operation will be:

(0, 0, 1, 0, 0)
(0, 0, 1, 1, 0)
(0, 0, 1, 2, 0)
(2, 2, 2, 2, 2)
(3, 2, 2, 2, 2)
(3, 2, 2, 3, 2)
(3, 2, 2, 4, 2)

The goal is to calculate the value of every counter after all operations.

Write a function:

def solution(N, A)

that, given an integer N and a non-empty array A consisting of M integers, returns a sequence of integers representing the values of the counters.

Result array should be returned as an array of integers.

For example, given:

A[0] = 3
A[1] = 4
A[2] = 4
A[3] = 6
A[4] = 1
A[5] = 4
A[6] = 4

the function should return [3, 2, 2, 4, 2], as explained above.

Write an efficient algorithm for the following assumptions:

N and M are integers within the range [1..100,000];
each element of array A is an integer within the range [1..N + 1].

• 첫번째 풀이
  문제 내용을 그대로 구현
  시간 초과

-두번째 풀이

def solution(N, A):
    # write your code in Python 3.8.10

    num_dic = {}
    max_num = 0
    for num in A:
        num-=1
        if num >= N:
            max_num +=find_max(num_dic)
            num_dic={}
        elif num in num_dic:
            num_dic[num]+=1
        else:
            num_dic[num] = 1
            
    num_list= [max_num]*N

    for key in num_dic.keys():
        num_list[key] += num_dic[key]    
    
    return num_list
    
def find_max(num_dic):
    max_val = 0 
    for key in num_dic.keys():
        max_val = max(max_val,num_dic[key])
    return max_val

• max 값을 찾는 것이 큰 오버헤드가 되는 것을 발견,
• 전체 배열에서 max값을 찾는것이 비효율적이라고 생각해서, count된것만 넣는 dict 생성
• dict에서 max값 찾아주는 함수 만듬