Izek Chen
1 min readJun 21, 2020

Coding Challenge — 2

This problem was recently asked by Airbnb

Given a sorted array, A, with possibly duplicated elements, find the indices of the first and last occurrences of a target element, x. Return -1 if the target is not found.

Example:

Input: A = [1,3,3,5,7,8,9,9,9,15], target = 9
Output: [6,8]

Input: A = [100, 150, 150, 153], target = 150
Output: [1,2]

Input: A = [1,2,3,4,5,6,10], target = 9
Output: [-1, -1]

Here is a function signature example:

class Solution: 
def getRange(self, arr, target):
# Fill this in.

# Test program
arr = [1, 2, 2, 2, 2, 3, 4, 7, 8, 8]
x = 2
print(Solution().getRange(arr, x))
# [1, 4]

Solution:

Time complexity O(n)

class Solution: 
def getRange(self, arr, target):
res = [0] * 2
find_first = 0

for i in range(len(arr)):
if arr[i] == x and find_first == 0:
find_first = 1
res[0] = i

if arr[i] == x:
res[1] = i
return res
Izek Chen
Izek Chen

Written by Izek Chen

Technical Account manager @ Google Cloud

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