[이취코] 정렬된 수열에서 특정 수의 개수 구하기 (Python)

 

처음에 짠 코드

n, m = list(map(int, input().split()))
arr = list(map(int, input().split()))

start = arr[0]
end = arr[-1]
count  = 0
while start <= end:
    mid = (start + end) // 2
    if arr[mid] == m:
        count = arr.count(m)
    elif arr[mid] > m:
        end = mid - 1
    else:
        start = mid + 1
print(count)

 

BS를 적용한 코드

from bisect import bisect_left, bisect_right

def count_by_range(array, left_value, right_value):
    right_index = bisect_right(array, right_value)
    left_index = bisect_left(array, left_value)
    return right_index - left_index

n, x = map(int, input().split())
array = list(map(int, input().split()))

count = count_by_range(array, x, x)

if count == 0:
    print(-1)

else:
    print(count)