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# Remove Duplicates From Sorted List

Difficulty: EASY Contributed By
Anshul Garg

Problem Statement
Suggest Edit

#### You are given a ‘Head’ of a sorted linked list. You can remove some values from the linked list. In the end, you must return a sorted linked list that contains no adjacent values that are equal.

##### For Example :
``````If the given linked list is: 1 -> 2 -> 2 -> 3

Then we will delete the duplicate value ‘2’ present in the linked list, and finally return the following list:
1 -> 2 -> 3
``````
##### Input Format :
``````The first line contains a single integer ‘T’ denoting the number of test cases, then each test case follows:

The first and only line of each test case contains the elements of the first linked list separated by a single space and terminated by -1. Hence, -1 would never be a list element.
``````
##### Output Format :
``````For each test case, print the final linked list. The elements of the linked list must be separated by a single space and terminated by -1.

Output for each test case will be printed in a separate line.
``````
##### Note :
``````You are not required to print anything; it has already been taken care of. Just implement the function.
``````
##### Constraints :
``````1 ≤ T ≤ 10
0 ≤ Length ≤ 10^5
1 ≤ data ≤ 10^6 and data != -1

Time limit: 1 sec
``````
##### Sample Input 1 :
``````2
1 2 2 3 -1
1 2 3 4 -1
``````
##### Sample Output 1 :
``````1 2 3 -1
1 2 3 4 -1
``````
##### Explanation For Sample Input 1 :
``````For test case 1, we will return 1 -> 2 -> 3 -> NULL, because :
We will delete the duplicate value ‘2’ present in the linked list, and finally return the following list:
1 -> 2 -> 3

For test case 2, we will return 1 -> 2 -> 3 -> 4 -> NULL, because the input list contains no duplicates, so we will return it as it is.
``````
##### Sample Input 2 :
``````2
1 -1
2 5 5 5 5 -1
``````
##### Sample Output 2 :
``````1 -1
2 5 -1
``````   Console