Modify array by replacing elements with their farthest co-prime number from a given range
Given an array arr[] consisting of N integers and two positive integers L and R, the task is to find the farthest co-prime number in the range [L, R] for every array element.
Examples:
Input: arr[] = {5, 150, 120}, L = 2, R = 250
Output: 249 7 247
Explanation:
The number which is co-prime with arr[0] and farthest from it is 249.
The number which is co-prime with arr[1] and farthest from it is 7.
The number which is co-prime with arr[2] and farthest from it is 247.Input: arr[] = {60, 246, 75, 103, 155, 110}, L = 2, R = 250
Output: 60 246 75 103 155 110
Approach: The given problem can be solved by iterating over the given range [L, R] for every array element and find the farthest element from it having GCD 1 with the array element. Follow the steps below to solve the problem:
- Traverse the given array arr[] and perform the following steps:
- Initialize two variables, say d as 0 and coPrime as -1, to store the farthest distance and the number coprime with the arr[i] respectively.
- Iterate over the given range [L, R] and perform the following steps:
- Update the value of d as the absolute difference of arr[i] and j.
- If the greatest common divisor of arr[i] and j is 1 and d is less than abs(arr[i] – j), then update the value of coPrime as j.
- Update the value of arr[i] as the coPrime.
- After completing the above steps, print the array arr[] as the resultant array.
Below is the implementation of the above approach:
C++
// C++ program for the above approach#include <bits/stdc++.h>using namespace std;// Function to calculate GCD// of the integers a and bint gcd(int a, int b){ // Base Case if (a == 0) return b; // Recursively find the GCD return gcd(b % a, a);}// Function to find the farthest// co-prime number over the range// [L, R] for each array elementvoid update(int arr[], int n){ // Traverse the array arr[] for (int i = 0; i < n; i++) { // Stores the distance // between j and arr[i] int d = 0; // Stores the integer coprime // which is coprime is arr[i] int coPrime = -1; // Traverse the range [2, 250] for (int j = 2; j <= 250; j++) { // If gcd of arr[i] and j is 1 if (gcd(arr[i], j) == 1 && d < abs(arr[i] - j)) { // Update the value of d d = abs(arr[i] - j); // Update the value // of coPrime coPrime = j; } } // Update the value of arr[i] arr[i] = coPrime; } // Print the array arr[] for (int i = 0; i < n; i++) cout << arr[i] << " ";}// Driver Codeint main(){ int arr[] = { 60, 246, 75, 103, 155, 110 }; int N = sizeof(arr) / sizeof(arr[0]); update(arr, N); return 0;} |
Java
// Java program for the above approachimport java.io.*;import java.lang.*;import java.util.*;class GFG{// Function to calculate GCD// of the integers a and bstatic int gcd(int a, int b){ // Base Case if (a == 0) return b; // Recursively find the GCD return gcd(b % a, a);}// Function to find the farthest// co-prime number over the range// [L, R] for each array elementstatic void update(int arr[], int n){ // Traverse the array arr[] for(int i = 0; i < n; i++) { // Stores the distance // between j and arr[i] int d = 0; // Stores the integer coprime // which is coprime is arr[i] int coPrime = -1; // Traverse the range [2, 250] for(int j = 2; j <= 250; j++) { // If gcd of arr[i] and j is 1 if (gcd(arr[i], j) == 1 && d < Math.abs(arr[i] - j)) { // Update the value of d d = Math.abs(arr[i] - j); // Update the value // of coPrime coPrime = j; } } // Update the value of arr[i] arr[i] = coPrime; } // Print the array arr[] for(int i = 0; i < n; i++) System.out.print(arr[i] + " ");}// Driver Codepublic static void main(String[] args){ int arr[] = { 60, 246, 75, 103, 155, 110 }; int N = arr.length; update(arr, N);}}// This code is contributed by Kingash |
Python3
# python 3 program for the above approachfrom math import gcd# Function to find the farthest# co-prime number over the range# [L, R] for each array elementdef update(arr, n): # Traverse the array arr[] for i in range(n): # Stores the distance # between j and arr[i] d = 0 # Stores the integer coprime # which is coprime is arr[i] coPrime = -1 # Traverse the range [2, 250] for j in range(2, 251, 1): # If gcd of arr[i] and j is 1 if (gcd(arr[i], j) == 1 and d < abs(arr[i] - j)): # Update the value of d d = abs(arr[i] - j) # Update the value # of coPrime coPrime = j # Update the value of arr[i] arr[i] = coPrime # Print the array arr[] for i in range(n): print(arr[i],end =" ")# Driver Codeif __name__ == '__main__': arr = [60, 246, 75, 103, 155, 110] N = len(arr) update(arr, N) # This code is contributed by ipg2016107. |
C#
// C# program for the above approachusing System;class GFG { // Function to calculate GCD // of the integers a and b static int gcd(int a, int b) { // Base Case if (a == 0) return b; // Recursively find the GCD return gcd(b % a, a); } // Function to find the farthest // co-prime number over the range // [L, R] for each array element static void update(int[] arr, int n) { // Traverse the array arr[] for (int i = 0; i < n; i++) { // Stores the distance // between j and arr[i] int d = 0; // Stores the integer coprime // which is coprime is arr[i] int coPrime = -1; // Traverse the range [2, 250] for (int j = 2; j <= 250; j++) { // If gcd of arr[i] and j is 1 if (gcd(arr[i], j) == 1 && d < Math.Abs(arr[i] - j)) { // Update the value of d d = Math.Abs(arr[i] - j); // Update the value // of coPrime coPrime = j; } } // Update the value of arr[i] arr[i] = coPrime; } // Print the array arr[] for (int i = 0; i < n; i++) Console.Write(arr[i] + " "); } // Driver Code public static void Main(string[] args) { int[] arr = { 60, 246, 75, 103, 155, 110 }; int N = arr.Length; update(arr, N); }}// This code is contributed by ukasp. |
Javascript
<script>// JavaScript program to implement// the above approach// Function to calculate GCD// of the integers a and bfunction gcd(a, b){ // Base Case if (a == 0) return b; // Recursively find the GCD return gcd(b % a, a);} // Function to find the farthest// co-prime number over the range// [L, R] for each array elementfunction update(arr, n){ // Traverse the array arr[] for(let i = 0; i < n; i++) { // Stores the distance // between j and arr[i] let d = 0; // Stores the integer coprime // which is coprime is arr[i] let coPrime = -1; // Traverse the range [2, 250] for(let j = 2; j <= 250; j++) { // If gcd of arr[i] and j is 1 if (gcd(arr[i], j) == 1 && d < Math.abs(arr[i] - j)) { // Update the value of d d = Math.abs(arr[i] - j); // Update the value // of coPrime coPrime = j; } } // Update the value of arr[i] arr[i] = coPrime; } // Print the array arr[] for(let i = 0; i < n; i++) document.write(arr[i] + " ");}// Driver code let arr = [ 60, 246, 75, 103, 155, 110 ]; let N = arr.length; update(arr, N) </script> |
Output:
247 5 248 250 2 249
Time Complexity: O((R – L) * N)
Auxiliary Space: O(1)
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