Maximum in an array that can make another array sorted

Last Updated : 17 Aug, 2022

Given two arrays among which one is almost sorted with one element being in the wrong position making the array unsorted, the task is to swap that element with the maximum element from the second array which can be used to make the first array sorted.

Examples:

Input: arr1 = {1, 3, 7, 4, 10}, arr2 = {2, 1, 5, 8, 9}
Output: 1 3 7 9 10
Swap 4 with 9.

Input: arr1 = {20, 1, 23}, arr2 = {50, 26, 7}
Output: Not Possible

Approach:

Get the index of the element which is making the array unsorted.
Get the maximum element from the second array satisfying the neighboring conditions of the element with wrong index i.e
1. max element >= arr[wrong index-1]
2. max element <= arr[wrong index+1] if wrong index+1 exists

Implementation:

C++

// C++ program to make array sorted
#include <bits/stdc++.h>
using namespace std;

// Function to check whether there is any
// swappable element present to make the first
// array sorted
bool swapElement(int arr1[], int arr2[], int n)
{

    // wrongIdx is the index of the element
    // which is making the first array unsorted
    int wrongIdx = 0;
    for (int i = 1; i < n; i++) {
        if (arr1[i] < arr1[i - 1]) 
            wrongIdx = i;
    }
    int maximum = INT_MIN;
    int maxIdx = -1;
    bool res = false;

    // Find the maximum element which satisfies the
    // the above mentioned neighboring conditions
    for (int i = 0; i < n; i++) {
        if (arr2[i] > maximum && arr2[i] >= arr1[wrongIdx - 1]) {
            if (wrongIdx + 1 <= n - 1 && 
                arr2[i] <= arr1[wrongIdx + 1]) {
                maximum = arr2[i];
                maxIdx = i;
                res = true;
            }
        }
    }

    // if res is true then swap the element
    // and make the first array sorted
    if (res)
        swap(arr1[wrongIdx], arr2[maxIdx]);

    return res;
}

// Function to print the sorted array if elements
// are swapped.
void getSortedArray(int arr1[], int arr2[], int n)
{
    if (swapElement(arr1, arr2, n))
        for (int i = 0; i < n; i++)
            cout << arr1[i] << " ";
    else
        cout << "Not Possible" << endl;
}

// Drivers code
int main()
{

    int arr1[] = { 1, 3, 7, 4, 10 };
    int arr2[] = { 2, 1, 6, 8, 9 };

    int n = sizeof(arr1) / sizeof(arr1[0]);

    getSortedArray(arr1, arr2, n);
}

Java

// Java program to make array sorted 

class GFG
{

// Function to check whether there 
// is any swappable element present 
// to make the first array sorted 
static boolean swapElement(int[] arr1, 
                           int[] arr2, int n) 
{

    // wrongIdx is the index of the 
    // element which is making the 
    // first array unsorted 
    int wrongIdx = 0;
    for (int i = 1; i < n; i++)
    {
        if (arr1[i] < arr1[i - 1])
        {
            wrongIdx = i;
        }
    }
    int maximum = Integer.MIN_VALUE;
    int maxIdx = -1;
    boolean res = false;

    // Find the maximum element which 
    // satisfies the above mentioned 
    // neighboring conditions 
    for (int i = 0; i < n; i++)
    {
        if (arr2[i] > maximum && 
            arr2[i] >= arr1[wrongIdx - 1]) 
        {
            if (wrongIdx + 1 <= n - 1 && 
                arr2[i] <= arr1[wrongIdx + 1]) 
            {
                maximum = arr2[i];
                maxIdx = i;
                res = true;
            }
        }
    }

    // if res is true then swap 
    // the element and make the 
    // first array sorted 
    if (res) 
    {
        swap(arr1, wrongIdx, arr2, maxIdx);
    }

    return res;
}

static void swap(int[] a, int wrongIdx,
                 int[] b, int maxIdx)
{
    int c = a[wrongIdx];
    a[wrongIdx] = b[maxIdx];
    b[maxIdx] = c;
}

// Function to print the sorted 
// array if elements are swapped. 
static void getSortedArray(int arr1[],  
                           int arr2[], int n)
{
    if (swapElement(arr1, arr2, n))
    {
        for (int i = 0; i < n; i++) 
        {
            System.out.print(arr1[i] + " ");
        }
    } 
    else 
    {
        System.out.println("Not Possible");
    }
}

// Driver code 
public static void main(String[] args)
{
    int arr1[] = {1, 3, 7, 4, 10};
    int arr2[] = {2, 1, 6, 8, 9};

    int n = arr1.length;

    getSortedArray(arr1, arr2, n);
}
}

// This code contributed by 29AjayKumar

Python3

# Python3 program to make array sorted 
import sys

# Function to check whether there is any 
# swappable element present to make the 
# first array sorted 
def swapElement(arr1, arr2, n) :

    # wrongIdx is the index of the element 
    # which is making the first array unsorted 
    wrongIdx = 0; 
    for i in range(1, n) : 
        if (arr1[i] < arr1[i - 1]) :
            wrongIdx = i 

    maximum = -(sys.maxsize - 1)
    maxIdx = -1
    res = False

    # Find the maximum element which satisfies  
    # the above mentioned neighboring conditions 
    for i in range(n) :
        if (arr2[i] > maximum and
            arr2[i] >= arr1[wrongIdx - 1]) :
            if (wrongIdx + 1 <= n - 1 and
                arr2[i] <= arr1[wrongIdx + 1]) : 
                maximum = arr2[i] 
                maxIdx = i
                res = True
        
    # if res is true then swap the element 
    # and make the first array sorted 
    if (res) : 
        (arr1[wrongIdx], 
         arr2[maxIdx]) = (arr2[maxIdx], 
                          arr1[wrongIdx])

    return res 

# Function to print the sorted array 
# if elements are swapped. 
def getSortedArray(arr1, arr2, n) :
    
    if (swapElement(arr1, arr2, n)) :
        
        for i in range(n) :
            print(arr1[i], end = " ")
    else :
        print("Not Possible")

# Driver code 
if __name__ == "__main__" :

    arr1 = [ 1, 3, 7, 4, 10 ]
    arr2 = [ 2, 1, 6, 8, 9 ]

    n = len(arr1)

    getSortedArray(arr1, arr2, n)

# This code is contributed by Ryuga

// C# program to make array sorted 
using System;

class GFG
{

// Function to check whether there 
// is any swappable element present 
// to make the first array sorted 
static bool swapElement(int[] arr1, 
                        int[] arr2, int n) 
{

    // wrongIdx is the index of the 
    // element which is making the 
    // first array unsorted 
    int wrongIdx = 0;
    for (int i = 1; i < n; i++) 
    {
        if (arr1[i] < arr1[i - 1])
        {
            wrongIdx = i;
        }
    }
    int maximum = int.MinValue;
    int maxIdx = -1;
    bool res = false;

    // Find the maximum element which 
    // satisfies the above mentioned 
    // neighboring conditions 
    for (int i = 0; i < n; i++)
    {
        if (arr2[i] > maximum && arr2[i] >= arr1[wrongIdx - 1])
        {
            if (wrongIdx + 1 <= n - 1 && 
                     arr2[i] <= arr1[wrongIdx + 1])
            {
                maximum = arr2[i];
                maxIdx = i;
                res = true;
            }
        }
    }

    // if res is true then swap the element 
    // and make the first array sorted 
    if (res) 
    {
        swap(arr1, wrongIdx, arr2, maxIdx);
    }

    return res;
}

static void swap(int[] a, int wrongIdx, 
                 int[] b, int maxIdx) 
{
    int c = a[wrongIdx];
    a[wrongIdx] = b[maxIdx];
    b[maxIdx] = c;
}

// Function to print the sorted array 
// if elements are swapped. 
static void getSortedArray(int []arr1, 
                           int []arr2, int n)
{
    if (swapElement(arr1, arr2, n))
    {
        for (int i = 0; i < n; i++) 
        {
            Console.Write(arr1[i] + " ");
        }
    } 
    else
    {
        Console.Write("Not Possible");
    }
}

// Driver Code 
public static void Main()
{
    int []arr1 = {1, 3, 7, 4, 10};
    int []arr2 = {2, 1, 6, 8, 9};

    int n = arr1.Length;

    getSortedArray(arr1, arr2, n);
}
}

// This code is contributed
// by PrinciRaj1992

JavaScript

<script>
    // Javascript program to make array sorted 
    
    // Function to check whether there 
    // is any swappable element present 
    // to make the first array sorted 
    function swapElement(arr1, arr2, n) 
    {

        // wrongIdx is the index of the 
        // element which is making the 
        // first array unsorted 
        let wrongIdx = 0;
        for (let i = 1; i < n; i++) 
        {
            if (arr1[i] < arr1[i - 1])
            {
                wrongIdx = i;
            }
        }
        let maximum = Number.MIN_VALUE;
        let maxIdx = -1;
        let res = false;

        // Find the maximum element which 
        // satisfies the above mentioned 
        // neighboring conditions 
        for (let i = 0; i < n; i++)
        {
            if (arr2[i] > maximum && arr2[i] >= arr1[wrongIdx - 1])
            {
                if (wrongIdx + 1 <= n - 1 && 
                         arr2[i] <= arr1[wrongIdx + 1])
                {
                    maximum = arr2[i];
                    maxIdx = i;
                    res = true;
                }
            }
        }

        // if res is true then swap the element 
        // and make the first array sorted 
        if (res) 
        {
            swap(arr1, wrongIdx, arr2, maxIdx);
        }

        return res;
    }

    function swap(a, wrongIdx, b, maxIdx) 
    {
        let c = a[wrongIdx];
        a[wrongIdx] = b[maxIdx];
        b[maxIdx] = c;
    }

    // Function to print the sorted array 
    // if elements are swapped. 
    function getSortedArray(arr1, arr2, n)
    {
        if (swapElement(arr1, arr2, n))
        {
            for (let i = 0; i < n; i++) 
            {
                document.write(arr1[i] + " ");
            }
        } 
        else
        {
            document.write("Not Possible");
        }
    }
    
    let arr1 = [1, 3, 7, 4, 10];
    let arr2 = [2, 1, 6, 8, 9];
  
    let n = arr1.length;
  
    getSortedArray(arr1, arr2, n);
    
    // This code is contributed by decode2207.
</script>

Output

1 3 7 9 10

Complexity Analysis:

Time Complexity: O(n)
Auxiliary Space: O(1)

Maximum adjacent difference in an array in its sorted form

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Maximum in an array that can make another array sorted

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