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Minimize sum of adjacent difference with removal of one element from array
  • Difficulty Level : Easy
  • Last Updated : 20 Mar, 2019

Given an array of positive integers of size greater than 2. The task is to find the minimum value of sum of consecutive difference modulus of array i.e. the value of |A1-A0|+|A2-A1|+|A3-A2|+……+|An-1-An-2|+|An-An-1| after removal of one element from array, where An represent the nth index of array element value.

Examples:

Input: arr[] = [1, 5, 3, 2, 10]
Output: 7
On removing 10, we get B = {1, 5, 3, 2} i.e. |1-5|+|5-3|+|3-2| = 4+2+1 = 7

Input: arr[] = [6, 12, 7, 8, 10, 15]
Output: 9
On removing 12, we get B = {6, 12, 7, 8, 10, 15} i.e. |6-7|+|7-8|+|8-10|+|10-15| = 1+1+2+5 = 9

The idea is to traverse the array from start to end, find the element in the array at which we get a maximum difference of consecutive modulus after its removal. Subtract the maximum value obtained from the total value calculated.



Below is the implementation of the above approach:

C++




// C++ implementation of above approach
#include <bits/stdc++.h>
using namespace std;
  
// Function to find the element
int findMinRemoval(int arr[], int n)
{
    // Value variable for storing the total value
    int temp, value = 0;
  
    // Declaring maximum value as zero
    int maximum = 0;
  
    // If array contains on element
    if (n == 1)
        return 0;
  
    for (int i = 0; i < n; i++) {
  
        // Storing the maximum value in temp variable
        if (i != 0 && i != n - 1) {
            value = value + abs(arr[i] - arr[i + 1]);
  
            // Adding the adjacent difference modulus
            // values of removed element. Removing adjacent
            // difference modulus value after removing element
            temp = abs(arr[i] - arr[i + 1]) + 
                   abs(arr[i] - arr[i - 1]) -
                   abs(arr[i - 1] - arr[i + 1]);
        }
        else if (i == 0) {
            value = value + abs(arr[i] - arr[i + 1]);
            temp = abs(arr[i] - arr[i + 1]);
        }
        else
            temp = abs(arr[i] - arr[i - 1]);
  
        maximum = max(maximum, temp);
    }
  
    // Returning total value-maximum value
    return (value - maximum);
}
  
// Drivers code
int main()
{
    int arr[] = { 1, 5, 3, 2, 10 };
    int n = sizeof(arr) / sizeof(arr[0]);
  
    cout << findMinRemoval(arr, n) << "\n";
    return 0;
}

Java




// Java implementation of the approach
class GFG 
{
  
// Function to find the element
static int findMinRemoval(int arr[], int n)
{
    // Value variable for storing the total value
    int temp, value = 0;
  
    // Declaring maximum value as zero
    int maximum = 0;
  
    // If array contains on element
    if (n == 1)
        return 0;
  
    for (int i = 0; i < n; i++)
    {
  
        // Storing the maximum value in temp variable
        if (i != 0 && i != n - 1
        {
            value = value + Math.abs(arr[i] - arr[i + 1]);
  
            // Adding the adjacent difference modulus
            // values of removed element. Removing adjacent
            // difference modulus value after removing element
            temp = Math.abs(arr[i] - arr[i + 1]) + 
                Math.abs(arr[i] - arr[i - 1]) -
                Math.abs(arr[i - 1] - arr[i + 1]);
        }
        else if (i == 0
        {
            value = value + Math.abs(arr[i] - arr[i + 1]);
            temp = Math.abs(arr[i] - arr[i + 1]);
        }
        else
            temp = Math.abs(arr[i] - arr[i - 1]);
  
        maximum = Math.max(maximum, temp);
    }
  
    // Returning total value-maximum value
    return (value - maximum);
}
  
// Drivers code
public static void main(String[] args) 
{
    int arr[] = { 1, 5, 3, 2, 10 };
    int n = arr.length;
    System.out.print(findMinRemoval(arr, n) + "\n");
}
}
  
// This code contributed by Rajput-Ji

Python 3




# Python 3 implementation of above approach
  
# Function to find the element
def findMinRemoval(arr, n):
  
    # Value variable for storing the
    # total value
    value = 0
  
    # Declaring maximum value as zero
    maximum = 0
  
    # If array contains on element
    if (n == 1):
        return 0
  
    for i in range( n):
  
        # Storing the maximum value in 
        # temp variable
        if (i != 0 and i != n - 1):
            value = value + abs(arr[i] - arr[i + 1])
  
            # Adding the adjacent difference modulus
            # values of removed element. Removing 
            # adjacent difference modulus value after
            # removing element
            temp = (abs(arr[i] - arr[i + 1]) + 
                    abs(arr[i] - arr[i - 1]) -
                    abs(arr[i - 1] - arr[i + 1]))
          
        elif (i == 0):
            value = value + abs(arr[i] - arr[i + 1])
            temp = abs(arr[i] - arr[i + 1])
      
        else:
            temp = abs(arr[i] - arr[i - 1])
  
        maximum = max(maximum, temp)
  
    # Returning total value-maximum value
    return (value - maximum)
  
# Drivers code
if __name__ == "__main__":
  
    arr = [ 1, 5, 3, 2, 10 ]
    n = len(arr)
  
    print(findMinRemoval(arr, n))
  
# This code is contributed by ita_c

C#




// C# implementation of the approach 
using System;
  
class GFG 
  
    // Function to find the element 
    static int findMinRemoval(int []arr, int n) 
    
        // Value variable for storing the total value 
        int temp, value = 0; 
      
        // Declaring maximum value as zero 
        int maximum = 0; 
      
        // If array contains on element 
        if (n == 1) 
            return 0; 
      
        for (int i = 0; i < n; i++) 
        
      
            // Storing the maximum value in temp variable 
            if (i != 0 && i != n - 1) 
            
                value = value + Math.Abs(arr[i] - arr[i + 1]); 
      
                // Adding the adjacent difference modulus 
                // values of removed element. Removing adjacent 
                // difference modulus value after removing element 
                temp = Math.Abs(arr[i] - arr[i + 1]) + 
                    Math.Abs(arr[i] - arr[i - 1]) - 
                    Math.Abs(arr[i - 1] - arr[i + 1]); 
            
            else if (i == 0) 
            
                value = value + Math.Abs(arr[i] - arr[i + 1]); 
                temp = Math.Abs(arr[i] - arr[i + 1]); 
            
            else
                temp = Math.Abs(arr[i] - arr[i - 1]); 
      
            maximum = Math.Max(maximum, temp); 
        
      
        // Returning total value-maximum value 
        return (value - maximum); 
    
      
    // Driver code 
    public static void Main() 
    
        int []arr = { 1, 5, 3, 2, 10 }; 
        int n = arr.Length; 
        Console.WriteLine(findMinRemoval(arr, n)); 
    
  
// This code contributed by Ryuga

PHP




<?php
// PHP implementation of above approach
  
// Function to find the element
function findMinRemoval($arr, $n)
{
    // Value variable for storing the total value
    $value = 0;
  
    // Declaring maximum value as zero
    $maximum = 0;
  
    // If array contains on element
    if ($n == 1)
        return 0;
    $temp=0;
    for ($i = 0; $i < $n; $i++) 
    {
  
        // Storing the maximum value in temp variable
        if ($i != 0 && $i != $n - 1) 
        {
            $value = $value + abs($arr[$i] - $arr[$i + 1]);
  
            // Adding the adjacent difference modulus
            // values of removed element. Removing adjacent
            // difference modulus value after removing element
            $temp = abs($arr[$i] - $arr[$i + 1]) + 
                abs($arr[$i] - $arr[$i - 1]) -
                abs($arr[$i - 1] - $arr[$i + 1]);
        }
        else if ($i == 0) 
        {
            $value = $value + abs($arr[$i] - $arr[$i + 1]);
            $temp = abs($arr[$i] - $arr[$i + 1]);
        }
        else
            $temp = abs($arr[$i] - $arr[$i - 1]);
  
        $maximum = max($maximum, $temp);
    }
  
    // Returning total value-maximum value
    return ($value - $maximum);
}
  
    // Drivers code
    $arr = array( 1, 5, 3, 2, 10 );
    $n = count($arr);
  
    echo findMinRemoval($arr, $n);
  
// This code is contributed by chandan_jnu
?>
Output:
7

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