In this post, we will look into deletion operation in an Array, i.e., how to delete an element from an Array, such as:
- Deleting Elements from an Array when it is Unsorted
- Deleting Elements from an Array when it is Sorted
Deleting Elements in an Array when it is Unsorted
In the delete operation, the element to be deleted is searched using the linear search, and then the delete operation is performed followed by shifting the elements.
// C++ program to implement delete operation in a // unsorted array #include <iostream> using namespace std;
// To search a key to be deleted int findElement( int arr[], int n, int key);
// Function to delete an element int deleteElement( int arr[], int n, int key)
{ // Find position of element to be deleted
int pos = findElement(arr, n, key);
if (pos == -1) {
cout << "Element not found" ;
return n;
}
// Deleting element
int i;
for (i = pos; i < n - 1; i++)
arr[i] = arr[i + 1];
return n - 1;
} // Function to implement search operation int findElement( int arr[], int n, int key)
{ int i;
for (i = 0; i < n; i++)
if (arr[i] == key)
return i;
return -1;
} // Driver's code int main()
{ int i;
int arr[] = { 10, 50, 30, 40, 20 };
int n = sizeof (arr) / sizeof (arr[0]);
int key = 30;
cout << "Array before deletion\n" ;
for (i = 0; i < n; i++)
cout << arr[i] << " " ;
// Function call
n = deleteElement(arr, n, key);
cout << "\n\nArray after deletion\n" ;
for (i = 0; i < n; i++)
cout << arr[i] << " " ;
return 0;
} // This code is contributed by shubhamsingh10 |
// C program to implement delete operation in a // unsorted array #include <stdio.h> // To search a key to be deleted int findElement( int arr[], int n, int key);
// Function to delete an element int deleteElement( int arr[], int n, int key)
{ // Find position of element to be deleted
int pos = findElement(arr, n, key);
if (pos == -1) {
printf ( "Element not found" );
return n;
}
// Deleting element
int i;
for (i = pos; i < n - 1; i++)
arr[i] = arr[i + 1];
return n - 1;
} // Function to implement search operation int findElement( int arr[], int n, int key)
{ int i;
for (i = 0; i < n; i++)
if (arr[i] == key)
return i;
return -1;
} // Driver's code int main()
{ int i;
int arr[] = { 10, 50, 30, 40, 20 };
int n = sizeof (arr) / sizeof (arr[0]);
int key = 30;
printf ( "Array before deletion\n" );
for (i = 0; i < n; i++)
printf ( "%d " , arr[i]);
// Function call
n = deleteElement(arr, n, key);
printf ( "\nArray after deletion\n" );
for (i = 0; i < n; i++)
printf ( "%d " , arr[i]);
return 0;
} |
// Java program to implement delete // operation in an unsorted array class Main {
// function to search a key to
// be deleted
static int findElement( int arr[], int n, int key)
{
int i;
for (i = 0 ; i < n; i++)
if (arr[i] == key)
return i;
return - 1 ;
}
// Function to delete an element
static int deleteElement( int arr[], int n, int key)
{
// Find position of element to be
// deleted
int pos = findElement(arr, n, key);
if (pos == - 1 ) {
System.out.println( "Element not found" );
return n;
}
// Deleting element
int i;
for (i = pos; i < n - 1 ; i++)
arr[i] = arr[i + 1 ];
return n - 1 ;
}
// Driver's Code
public static void main(String args[])
{
int i;
int arr[] = { 10 , 50 , 30 , 40 , 20 };
int n = arr.length;
int key = 30 ;
System.out.println( "Array before deletion" );
for (i = 0 ; i < n; i++)
System.out.print(arr[i] + " " );
// Function call
n = deleteElement(arr, n, key);
System.out.println( "\n\nArray after deletion" );
for (i = 0 ; i < n; i++)
System.out.print(arr[i] + " " );
}
} |
# Python program to delete an element # from an unsorted array # Driver's code if __name__ = = '__main__' :
# Declaring array and key to delete
arr = [ 10 , 50 , 30 , 40 , 20 ]
key = 30
print ( "Array before deletion:" )
print (arr)
# deletes key if found in the array
# otherwise shows error not in list
arr.remove(key)
print ( "Array after deletion" )
print (arr)
# This code is contributed by Aditi Sharma.
|
// C# program to implement delete // operation in an unsorted array using System;
class main {
// Function to search a
// key to be deleted
static int findElement( int [] arr, int n, int key)
{
int i;
for (i = 0; i < n; i++)
if (arr[i] == key)
return i;
return -1;
}
// Function to delete an element
static int deleteElement( int [] arr, int n, int key)
{
// Find position of element
// to be deleted
int pos = findElement(arr, n, key);
if (pos == -1) {
Console.WriteLine( "Element not found" );
return n;
}
// Deleting element
int i;
for (i = pos; i < n - 1; i++)
arr[i] = arr[i + 1];
return n - 1;
}
// Driver Code
public static void Main()
{
int i;
int [] arr = { 10, 50, 30, 40, 20 };
int n = arr.Length;
int key = 30;
Console.Write( "Array before deletion " );
for (i = 0; i < n; i++)
Console.Write(arr[i] + " " );
Console.WriteLine();
// Function call
n = deleteElement(arr, n, key);
Console.Write( "Array after deletion " );
for (i = 0; i < n; i++)
Console.Write(arr[i] + " " );
}
} // This code is contributed by vt_m. |
// Java script program to implement delete // operation in an unsorted array // function to search a key to
// be deleted
function findElement(arr,n,key)
{
let i;
for (i = 0; i < n; i++)
if (arr[i] == key)
return i;
return -1;
}
// Function to delete an element
function deleteElement(arr,n,key)
{
// Find position of element to be
// deleted
let pos = findElement(arr, n, key);
if (pos == -1)
{
document.write( "Element not found" );
return n;
}
// Deleting element
let i;
for (i = pos; i< n - 1; i++)
arr[i] = arr[i + 1];
return n - 1;
}
// Driver Code
let i;
let arr = [10, 50, 30, 40, 20];
let n = arr.length;
let key = 30;
document.write( "Array before deletion<br>" );
for (i=0; i<n; i++)
document.write(arr[i] + " " );
n = deleteElement(arr, n, key);
document.write( "<br><br>Array after deletion<br>" );
for (i=0; i<n; i++)
document.write(arr[i]+ " " );
// This code is contributed by sravan kumar Gottumukkala |
<?php // PHP program to implement delete // operation in an unsorted array // To search a key to be deleted function findElement(& $arr , $n , $key )
{ for ( $i = 0; $i < $n ; $i ++)
if ( $arr [ $i ] == $key )
return $i ;
return -1;
} // Function to delete an element function deleteElement(& $arr , $n , $key )
{ // Find position of element to
// be deleted
$pos = findElement( $arr , $n , $key );
if ( $pos == -1)
{
echo "Element not found" ;
return $n ;
}
// Deleting element
for ( $i = $pos ; $i < $n - 1; $i ++)
$arr [ $i ] = $arr [ $i + 1];
return $n - 1;
} // Driver code $arr = array (10, 50, 30, 40, 20);
$n = count ( $arr );
$key = 30;
echo "Array before deletion\n" ;
for ( $i = 0; $i < $n ; $i ++)
echo $arr [ $i ] . " " ;
// Function call $n = deleteElement( $arr , $n , $key );
echo "\nArray after deletion\n" ;
for ( $i = 0; $i < $n ; $i ++)
echo $arr [ $i ] . " " ;
// This code is contributed by // Rajput-Ji ?> |
Array before deletion 10 50 30 40 20 Array after deletion 10 50 40 20
Time Complexity: O(N)
Auxiliary Space: O(1)
Deleting Elements in an Array when it is Sorted
In the delete operation, the element to be deleted is searched using binary search, and then the delete operation is performed followed by shifting the elements.
Below is the implementation of the above approach:
// C++ program to implement delete operation in a // sorted array #include <bits/stdc++.h> using namespace std;
// To search a key to be deleted int binarySearch( int arr[], int low, int high, int key);
/* Function to delete an element */ int deleteElement( int arr[], int n, int key)
{ // Find position of element to be deleted
int pos = binarySearch(arr, 0, n - 1, key);
if (pos == -1) {
cout << "Element not found" ;
return n;
}
// Deleting element
int i;
for (i = pos; i < n - 1; i++)
arr[i] = arr[i + 1];
return n - 1;
} int binarySearch( int arr[], int low, int high, int key)
{ if (high < low)
return -1;
int mid = (low + high) / 2;
if (key == arr[mid])
return mid;
if (key > arr[mid])
return binarySearch(arr, (mid + 1), high, key);
return binarySearch(arr, low, (mid - 1), key);
} // Driver code int main()
{ int i;
int arr[] = { 10, 20, 30, 40, 50 };
int n = sizeof (arr) / sizeof (arr[0]);
int key = 30;
cout << "Array before deletion\n" ;
for (i = 0; i < n; i++)
cout << arr[i] << " " ;
// Function call
n = deleteElement(arr, n, key);
cout << "\n\nArray after deletion\n" ;
for (i = 0; i < n; i++)
cout << arr[i] << " " ;
} // This code is contributed by shubhamsingh10 |
// C program to implement delete operation in a // sorted array #include <stdio.h> // To search a key to be deleted int binarySearch( int arr[], int low, int high, int key);
/* Function to delete an element */ int deleteElement( int arr[], int n, int key)
{ // Find position of element to be deleted
int pos = binarySearch(arr, 0, n - 1, key);
if (pos == -1) {
printf ( "Element not found" );
return n;
}
// Deleting element
int i;
for (i = pos; i < n - 1; i++)
arr[i] = arr[i + 1];
return n - 1;
} int binarySearch( int arr[], int low, int high, int key)
{ if (high < low)
return -1;
int mid = (low + high) / 2;
if (key == arr[mid])
return mid;
if (key > arr[mid])
return binarySearch(arr, (mid + 1), high, key);
return binarySearch(arr, low, (mid - 1), key);
} // Driver code int main()
{ int i;
int arr[] = { 10, 20, 30, 40, 50 };
int n = sizeof (arr) / sizeof (arr[0]);
int key = 30;
printf ( "Array before deletion\n" );
for (i = 0; i < n; i++)
printf ( "%d " , arr[i]);
// Function call
n = deleteElement(arr, n, key);
printf ( "\n\nArray after deletion\n" );
for (i = 0; i < n; i++)
printf ( "%d " , arr[i]);
} |
// Java program to delete an // element from a sorted array class Main {
// Binary search
static int binarySearch( int arr[], int low, int high,
int key)
{
if (high < low)
return - 1 ;
int mid = (low + high) / 2 ;
if (key == arr[mid])
return mid;
if (key > arr[mid])
return binarySearch(arr, (mid + 1 ), high, key);
return binarySearch(arr, low, (mid - 1 ), key);
}
/* Function to delete an element */
static int deleteElement( int arr[], int n, int key)
{
// Find position of element to be deleted
int pos = binarySearch(arr, 0 , n - 1 , key);
if (pos == - 1 ) {
System.out.println( "Element not found" );
return n;
}
// Deleting element
int i;
for (i = pos; i < n - 1 ; i++)
arr[i] = arr[i + 1 ];
return n - 1 ;
}
/* Driver Code */
public static void main(String[] args)
{
int i;
int arr[] = { 10 , 20 , 30 , 40 , 50 };
int n = arr.length;
int key = 30 ;
System.out.print( "Array before deletion:\n" );
for (i = 0 ; i < n; i++)
System.out.print(arr[i] + " " );
// Function call
n = deleteElement(arr, n, key);
System.out.print( "\n\nArray after deletion:\n" );
for (i = 0 ; i < n; i++)
System.out.print(arr[i] + " " );
}
} |
# Python program to implement delete operation in a # sorted array # /* Function to delete an element */ def deleteElement(arr, n, key):
# Find position of element to be deleted
pos = binarySearch(arr, 0 , n - 1 , key)
if (pos = = - 1 ):
print ( "Element not found" )
return n
# Deleting element
for i in range (pos, n - 1 ):
arr[i] = arr[i + 1 ]
return n - 1
# To search a key to be deleted def binarySearch(arr, low, high, key):
if (high < low):
return - 1
mid = (low + high) / / 2
if (key = = arr[mid]):
return mid
if (key > arr[mid]):
return binarySearch(arr, (mid + 1 ), high, key)
return binarySearch(arr, low, (mid - 1 ), key)
# Driver code if __name__ = = "__main__" :
arr = [ 10 , 20 , 30 , 40 , 50 ]
n = len (arr)
key = 30
print ( "Array before deletion" )
for i in range (n):
print (arr[i], end = " " )
# Function call
n = deleteElement(arr, n, key)
print ( "\n\nArray after deletion" )
for i in range (n):
print (arr[i], end = " " )
# This code is contributed by shubhamsingh10 |
// C# program to delete an // element from a sorted array using System;
public class GFG {
// Binary search
static int binarySearch( int [] arr, int low, int high,
int key)
{
if (high < low)
return -1;
int mid = (low + high) / 2;
if (key == arr[mid])
return mid;
if (key > arr[mid])
return binarySearch(arr, (mid + 1), high, key);
return binarySearch(arr, low, (mid - 1), key);
}
/* Function to delete an element */
static int deleteElement( int [] arr, int n, int key)
{
// Find position of element to be deleted
int pos = binarySearch(arr, 0, n - 1, key);
if (pos == -1) {
Console.WriteLine( "Element not found" );
return n;
}
// Deleting element
int i;
for (i = pos; i < n - 1; i++)
arr[i] = arr[i + 1];
return n - 1;
}
/* Driver Code */
public static void Main()
{
int i;
int [] arr = { 10, 20, 30, 40, 50 };
int n = arr.Length;
int key = 30;
Console.Write( "Array before deletion:\n" );
for (i = 0; i < n; i++)
Console.Write(arr[i] + " " );
// Function call
n = deleteElement(arr, n, key);
Console.Write( "\n\nArray after deletion:\n" );
for (i = 0; i < n; i++)
Console.Write(arr[i] + " " );
}
} // This code is contributed by Rajput-Ji |
<script> // JavaScript program to delete an // element from a sorted array // binary search
function binarySearch(arr, low, high, key)
{
if (high < low)
return -1;
let mid = (low + high) / 2;
if (key == arr[mid])
return mid;
if (key > arr[mid])
return binarySearch(arr, (mid + 1), high, key);
return binarySearch(arr, low, (mid - 1), key);
}
/* Function to delete an element */
function deleteElement( arr, n, key)
{
// Find position of element to be deleted
let pos = binarySearch(arr, 0, n - 1, key);
if (pos == -1) {
document.write( "Element not found" );
return n;
}
// Deleting element
let i;
for (i = pos; i < n - 1; i++)
arr[i] = arr[i + 1];
return n - 1;
}
/* Driver Code */
let i;
let arr = [ 10, 20, 30, 40, 50 ];
let n = arr.length;
let key = 30;
document.write( "Array before deletion:\n" );
for (i = 0; i < n; i++)
document.write(arr[i] + " " );
n = deleteElement(arr, n, key);
document.write( "<br>" + "Array after deletion:\n" );
for (i = 0; i < n; i++)
document.write(arr[i] + " " );
// this code is contributed by shivanisinghss2110
</script> |
Array before deletion 10 20 30 40 50 Array after deletion 10 20 40 50
Time Complexity: O(N). In the worst case all elements may have to be moved
Auxiliary Space: O(log N). An implicit stack will be used