# [algorithms] max counters

mgm-dev·2021년 4월 19일
0

## codility algorithms

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4/5 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 = 3
A = 4
A = 4
A = 6
A = 1
A = 4
A = 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 = 3
A = 4
A = 4
A = 6
A = 1
A = 4
A = 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].

## my solution

def solution(N, A):
# write your code in Python 3.6
counters =  * N
max_counter = 0
for a in A:
if a <= N:
counters[a-1] +=1
if counters[a-1] > max_counter:
max_counter = counters[a-1]
else:
counters = [max_counter] * N

return counters

## faster solution

def solution(N, A):
# write your code in Python 3.6
counters =  * N
max_counter = 0
last_update = 0

for K,X in enumerate(A):
if 1 <= X <= N:
counters[X-1] = max(counters[X-1], last_update)
counters[X-1] += 1
max_counter = max(counters[X-1], max_counter)
elif A[K] == (N + 1):
last_update = max_counter

for i in range(N):
counters[i] = max(counters[i], last_update)

return counters