New update is available. Click here to update.

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

Find Median from Data Stream

Contributed by

imObscure

Medium

0/80

Avg time to solve 20 mins

Success Rate 76 %

0 upvotes

Problem Statement

The median is the middle value in an ordered integer list. If the size of the list is even, there is no middle value and the median is the mean of the two middle values.

Example:

Median for ‘arr’ = [1,2,3,4,5] is 3.
Median for ‘arr’ = [1,2,3,4] is (2+3)/2 = 2.5.

Implement the MedianFinder class:

MedianFinder() initialises the MedianFinder object.

1. Void addNum(int ‘num’) adds the integer ‘num’ from the datastream to the data structure.

2. Double findMedian() returns the median of all elements so far.

Note : Answers within 10^-5 of actual answer will be accepted.

Example:

Input: 
5
1 1
1 2
2
1 5
2

Output:     
1.5
2

Explanation:
MedianFinder() initialises the MedianFinder object.
Add 1 to the data structure ‘arr’, so arr = [1].
Add 2 to arr, so arr = [1,2]
Find Median of current arr, that is (1+2)/2 = 1.5.
Add 5 to arr, so arr = [1,2,5]
Find Median of current arr, that is 2.0.

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

Input Format :

The first line of the input contains an integer, ‘T’, denoting the number of test cases.

The First line of each test case contains an integer, ‘N’ denoting the number of calls to addNum and findMedian.

Output format :

Return an integer if the call is made to findMedian.

Constraints :

1  <= T <= 10
-100000 <= nums <= 100000
1 <= N <= 50000
There would be at least 1 element in the data structure before calling findMedian.
Time Limit: 1 sec

Sample Input 1 :

Sample Output 1 :

Explanation Of Sample Input 1 :

Test 1:
MedianFinder() initialises the MedianFinder object.
Add 1 to the data structure ‘arr’, so arr = [1].
Add 2 to arr, so arr = [1,2]
Find Median of the current arr, that is (1+2)/2 = 1.5.
Add 5 to arr, so arr = [1,2,5]
Find Median of current arr, that is 2.0

Test 2:
MedianFinder() initialises the MedianFinder object.
Add 1 to the data structure ‘arr’, so arr = [1].
Find Median of current arr, that is 1.0.
Add 5 to arr, so arr = [1,5]
Find Median of current arr, that is (1+5)/2 = 3.0.

Sample Input 2 :

Sample Output 2 :

2.0
3
3

Auto

Console