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Print n smallest elements from given array in their original order
• Difficulty Level : Easy
• Last Updated : 01 Mar, 2021

We are given an array of m-elements, we need to find n smallest elements from the array but they must be in the same order as they are in given array.
Examples:

```Input : arr[] = {4, 2, 6, 1, 5},
n = 3
Output : 4 2 1
Explanation :
1, 2 and 4 are 3 smallest numbers and
4 2 1 is their order in given array.

Input : arr[] = {4, 12, 16, 21, 25},
n = 3
Output : 4 12 16
Explanation :
4, 12 and 16 are 3 smallest numbers and
4 12 16 is their order in given array.```

Make a copy of original array and then sort copy array. After sorting the copy array, save all n smallest numbers. Further for each element in original array, check whether it is in n-smallest number or not if it present in n-smallest array then print it otherwise move forward.

Make copy_arr[]sort(copy_arr)For all elements in arr[] –   Find arr[i] in n-smallest element of copy_arr  If found then print the element

Below is the implementation of above approach :

## C++

 `// CPP for printing smallest n number in order``#include ``using` `namespace` `std;` `// Function to print smallest n numbers``void` `printSmall(``int` `arr[], ``int` `asize, ``int` `n)``{``    ``// Make copy of array``    ``vector<``int``> copy_arr(arr, arr + asize);` `    ``// Sort copy array``    ``sort(copy_arr.begin(), copy_arr.begin() + asize);` `    ``// For each arr[i] find whether``    ``// it is a part of n-smallest``    ``// with binary search``    ``for` `(``int` `i = 0; i < asize; ++i)``        ``if` `(binary_search(copy_arr.begin(),``                ``copy_arr.begin() + n, arr[i]))``            ``cout << arr[i] << ``" "``;``}` `// Driver program``int` `main()``{``    ``int` `arr[] = { 1, 5, 8, 9, 6, 7, 3, 4, 2, 0 };``    ``int` `asize = ``sizeof``(arr) / ``sizeof``(arr);   ``    ``int` `n = 5;``    ``printSmall(arr, asize, n);``    ``return` `0;``}`

## Java

 `// Java for printing smallest n number in order``import` `java.util.*;` `class` `GFG``{`  `// Function to print smallest n numbers``static` `void` `printSmall(``int` `arr[], ``int` `asize, ``int` `n)``{``    ``// Make copy of array``    ``int` `[]copy_arr = Arrays.copyOf(arr,asize);` `    ``// Sort copy array``    ``Arrays.sort(copy_arr);` `    ``// For each arr[i] find whether``    ``// it is a part of n-smallest``    ``// with binary search``    ``for` `(``int` `i = ``0``; i < asize; ++i)``    ``{``        ``if` `(Arrays.binarySearch(copy_arr,``0``,n, arr[i])>-``1``)``            ``System.out.print(arr[i] + ``" "``);``    ``}``}` `// Driver code``public` `static` `void` `main(String[] args)``{``    ``int` `arr[] = { ``1``, ``5``, ``8``, ``9``, ``6``, ``7``, ``3``, ``4``, ``2``, ``0` `};``    ``int` `asize = arr.length;``    ``int` `n = ``5``;``    ``printSmall(arr, asize, n);``}``}` `// This code is contributed by Princi Singh`

## Python3

 `# Python3 for printing smallest n number in order` `# Function for binary_search``def` `binary_search(arr, low, high, ele):``    ``while` `low < high:``        ``mid ``=` `(low ``+` `high) ``/``/` `2``        ``if` `arr[mid] ``=``=` `ele:``            ``return` `mid``        ``elif` `arr[mid] > ele:``            ``high ``=` `mid``        ``else``:``            ``low ``=` `mid ``+` `1``    ``return` `-``1` `# Function to print smallest n numbers``def` `printSmall(arr, asize, n):` `    ``# Make copy of array``    ``copy_arr ``=` `arr.copy()` `    ``# Sort copy array``    ``copy_arr.sort()` `    ``# For each arr[i] find whether``    ``# it is a part of n-smallest``    ``# with binary search``    ``for` `i ``in` `range``(asize):``        ``if` `binary_search(copy_arr, low ``=` `0``,``                         ``high ``=` `n, ele ``=` `arr[i]) > ``-``1``:``            ``print``(arr[i], end ``=` `" "``)` `# Driver Code``if` `__name__ ``=``=` `"__main__"``:``    ``arr ``=` `[``1``, ``5``, ``8``, ``9``, ``6``, ``7``, ``3``, ``4``, ``2``, ``0``]``    ``asize ``=` `len``(arr)``    ``n ``=` `5``    ``printSmall(arr, asize, n)` `# This code is conributed by``# sanjeev2552`

## C#

 `// C# for printing smallest n number in order``using` `System;    ` `class` `GFG``{`  `// Function to print smallest n numbers``static` `void` `printSmall(``int` `[]arr, ``int` `asize, ``int` `n)``{``    ``// Make copy of array``    ``int` `[]copy_arr = ``new` `int``[asize];``    ``Array.Copy(arr, copy_arr, asize);` `    ``// Sort copy array``    ``Array.Sort(copy_arr);` `    ``// For each arr[i] find whether``    ``// it is a part of n-smallest``    ``// with binary search``    ``for` `(``int` `i = 0; i < asize; ++i)``    ``{``        ``if` `(Array.BinarySearch(copy_arr, 0, n, arr[i])>-1)``            ``Console.Write(arr[i] + ``" "``);``    ``}``}` `// Driver code``public` `static` `void` `Main(String[] args)``{``    ``int` `[]arr = { 1, 5, 8, 9, 6, 7, 3, 4, 2, 0 };``    ``int` `asize = arr.Length;``    ``int` `n = 5;``    ``printSmall(arr, asize, n);``}``}` `// This code has been contributed by 29AjayKumar`

Output :

`1 3 4 2 0 `

Time Complexity: O(n * log(n))

Auxiliary Space: O(n)
For making a copy of array we need space complexity of O(n) and then for sorting we will need complexity of order O(n log n). Further for each element in arr[] we are performing searching in copy_arr[], which will result O(n) for linear search but we can improve it by applying binary search and hence our overall time complexity will be O(n log n).

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