### arraysIntersection 
from typing import *
def f_gold(arr1: List[int], arr2: List[int], arr3: List[int]
) -> List[int]:
    def find(arr, val):
        left, right = 0, len(arr) - 1
        while left < right:
            mid = (left + right) >> 1
            if arr[mid] >= val:
                right = mid
            else:
                left = mid + 1
        return arr[left] == val
    res = []
    for num in arr1:
        if find(arr2, num) and find(arr3, num):
            res.append(num)
    return res