Sort Array
You are given an array consisting of 'N' positive integers where each integer is either 0 or 1 or 2. Your task is to sort the given array in non-decreasing order.

Note :

1. The array consists of only 3 distinct integers 0, 1, 2. 2. The array is non-empty.

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 size of the array. The second line of each test case contains N space-separated integers, representing the elements of the array.

Output Format :

The only line of output of each test case consists of N integers, denoting the sorted order of elements in the given array. Print the output of each test case 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

Question

Sort Array

You are given an array consisting of 'N' positive integers where each integer is either 0 or 1 or 2. Your task is to sort the given array in non-decreasing order.

Note :

1. The array consists of only 3 distinct integers 0, 1, 2.
2. The array is non-empty.

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 size of the array.

The second line of each test case contains N space-separated integers, representing the elements of the array.

Output Format :

The only line of output of each test case consists of N integers, denoting the sorted order of elements in the given array. 

Print the output of each test case 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 <= 100
1 <= N <= 10^4
0 <= arr[i] <= 2

where arr[i] is the array element at index 'i'.

Time Limit: 1 sec

Accepted Answer

1) The sort() method allows us to sort elements of an array in place. Besides returning the sorted array, the sort()
method changes the positions of the elements in the original array.

2) By default, the sort() method sorts the array elements in ascending order with the smallest value first and largest
value last.

3) The sort() method casts elements to strings and compares the strings lexicographically to determine the orders.
To sort an array of integers in JS :

Code :

let numbers = [0, 1, 20, 3, 30, 2, 10];
numbers.sort((a, b) => a - b);

console.log(numbers); //[0,1,2,3,10,20,30]

The compare() function accepts two arguments a and b. The sort() method will sort elements based on the return
value of the compare() function with the following rules:

i) If compare(a,b) is less than zero, the sort() method sorts a to a lower index than b. In other words, a
will come first.

ii) If compare(a,b) is greater than zero, the sort() method sort b to a lower index than a, i.e., b will come
first.

iii) If compare(a,b) returns zero, the sort() method considers a equals b and leaves their positions
unchanged.

Accepted Answer

Using STL

Algorithm

The simplest possible approach will be to use the in-built sort function which is available in most of programming languages.
So after applying the algorithm, we can simply return the array.

Space Complexity: O(1)Explanation:

O(1)

Constant extra space is required.

Time Complexity: O(nlogn)Explanation:

O(N*logN), where ‘N’ is the number of elements in the array.

As we are sorting the given array, the time complexity is O(N*log(N))

Accepted Answer

Three Pointer Approach

Algorithm

Since sorting using the in-built library is trivial and we are also given that there are only three distinct integers in the array, we can use three-pointers to solve this problem. We are going to use a technique which is an application of the famous Dutch national flag theorem.
Let low = 0 and high = n - 1 initially.
For i = 0 to i <= high do the following:
- If arr[i] = 0, then we know that this element should be on the lower end of the array so we can swap arr[i] with arr[low] and increment low i.e low += 1.
- Else if arr[i] = 2, then we know that this element should be on the last of the array, so we swap arr[i] and arr[high] and do i += 1 and high -= 1.

Space Complexity: O(1)Explanation:

O(1)

Constant extra space is used.

Time Complexity: O(n)Explanation:

O(N), where ‘N’ is the number of elements in the array.

Since we are traversing the array once, the time complexity is O(N)

You are given an array consisting of 'N' positive integers where each integer is either 0 or 1 or 2. Your task is to sort the given array in non-decreasing order.

Note :

Input Format :

Output Format :

Note :

Constraints :

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