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Problem

Submissions

Move Zeros To Left

Contributed by

Prateek_18cb

Easy

0/40

Avg time to solve 10 mins

Success Rate 90 %

26 upvotes

Problem Statement

You are given an array 'ARR' of integers. Your task is to modify the array so that all the array elements having zero values get pushed to the left and all the array elements having non-zero value come after them while maintaining their relative order.

For example :

Consider the array { 1, 1, 0, 2, 0 }. 
For the given array the modified array should be {0,0,1,1,2} . 
Arrays { 0, 0, 1, 2, 1 } and  { 0, 0, 2, 1, 1 } are not the correctly reorganized array even if they have all the zero values pushed to the left as in both the arrays the relative order of non-zero elements is not maintained.

Follow Up :

Can you solve the problem in linear time, and constant space?

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

Input Format :

The first line of the input contains an integer 'T' representing the number of test cases or queries to be processed.
Then the 'T' test case follows.
The first line of each test case contains an integer 'N' denoting the number of elements in the array 'ARR'.
The second line of each test contains 'N' space-separated integers denoting the array elements.

Output Format :

For each test case, print the modified array in a separate line.

Note :

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

Constraints :

1 <= T <= 10
1 <= N <= 10^5
-10^9 <= ARR[i] <= 10^9

Where 'T' denotes the number of test cases, 'N' denotes the number of elements in the array ‘ARR’ respectively, and 'ARR[i]' denotes the ’i-th’ element of the array 'ARR'. 

Time limit: 1 second

Sample Input 1 :

Sample Output 1 :

0 0 1 2 1
0 0 1

Explanation for sample input 1 :

For the first test case, the given array is { 1, 2, 0, 0, 1 }, if we move all the zeros to the left the modified array becomes { 0, 0, 1, 2, 1} which is our final answer. 

For the second test case, the given array is { 1, 0, 0}, if we move all the zeros to the left the modified array becomes { 0, 0, 1} which is our final answer.

Sample Input 2 :

1
5
1 2 3 4 5

Sample Output 2 :

1 2 3 4 5

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