New update is available. Click here to update.

First and Last Position of an Element In Sorted Array

EASY

15 mins

393 upvotes

Binary Search

Arrays

Solve problems & track your progress

Checkout your overall progress in every topic here

Become

Sensei

in DSA topics

Open the topic and solve more problems associated with it to improve your skills

Check out the skill meter for every topic

See how many problems you are left with to solve for cracking any stage. Score more than zero to get your progress counted.

Problem

Submissions

First and Last Position of an Element In Sorted Array

Last Updated: 23 Feb, 2023

Easy

0/40

Avg time to solve 15 mins

Success Rate 85 %

393 upvotes

Problem Statement

You have been given a sorted array/list ARR consisting of ‘N’ elements. You are also given an integer ‘K’.

Now, your task is to find the first and last occurrence of ‘K’ in ARR.

Note :

1. If ‘K’ is not present in the array, then the first and the last occurrence will be -1. 
2. ARR may contain duplicate elements.

For example, if ARR = [0, 1, 1, 5] and K = 1, then the first and last occurrence of 1 will be 1(0 - indexed) and 2.

Detailed explanation ( Input/output format, Notes, Images )

Input Format

The first line of input contains an integer 'T' which denotes the number of test cases or queries to be run. Then the test cases follow.

The first line of each test case contains two single-space separated integers ‘N’ and ‘K’, respectively.

The second line of each test case contains ‘N’ single space-separated integers denoting the elements of the array/list ARR.

Output Format :

Return two single-space separated integers denoting the first and the last occurrence of ‘K’ in ARR, respectively.

Note:

You do not need to print anything; it has already been taken care of. Just implement the given function.

Constraints:

1 <= T <= 100
1 <= N <= 5000
0 <= K <= 10^5
0 <= ARR[i] <=10^5

Time Limit : 1 second

Sample Input 1:

2
6 3
0 5 5 6 6 6
8 2
0 0 1 1 2 2 2 2

Sample output 1:

-1 -1 
4 7

Explanation of Sample output 1:

For the first test case, 3 is not present in the array. Hence the first and last occurrence of 3 is -1 and -1.

For the second test case, the first occurrence of 2 in at index 4 and last occurrence is at index 7.

Sample Input 2:

Sample output 2:

0 3
0 0

Auto

Console