Number of occurrence of x in array

def left_index(l,r,arr,target):
    if l>r:
        return -1
    mid= (l+r)//2
    if arr[mid]==target and (mid==0 or arr[mid-1]!=target):
        return mid
    elif arr[mid]>=target:
        return left_index(l,mid-1,arr,target)
    else:
        return left_index(mid+1,r,arr,target)

def right_index(l,r,arr,target):
    if l>r:
        return -1
    mid=(l+r)//2
    if arr[mid]==target and (mid==len(arr)-1 or arr[mid+1]!=target):
        return mid
    elif arr[mid]>target:
        return right_index(l,mid-1,arr,target)
    else:
        return right_index(mid+1,r,arr,target)

class Solution:
    def countFreq(self, arr, target):
        first=left_index(0,len(arr)-1,arr,target)
        last=right_index(0,len(arr)-1,arr,target)
        return last-first+1 if first!=-1 else 0

#M-2 Using prebuild functions

from bisect import bisect_left,bisect_right
class Solution:
    def countFreq(self, arr, target):
        first=bisect_left(arr,target)
        last=bisect_right(arr,target) #it gives the next element index after the target
        return last-first if first<len(arr) and arr[first]==target else 0