Maximize product of two closest numbers of other array for every element in given array

// Java implementation for the above approach

import java.io.*;
import java.util.*;

class GFG {

    // Function to find the maximum product of
    // Closest two elements in second array
    // for every element in the first array
    public static int[] maxProdClosest(int[] arr1,
                                       int[] arr2)
    {

        // Find the length of both arrays
        int M = arr1.length, N = arr2.length;

        // Initialize an array to store
        // the result for every element
        int[] ans = new int[M];

        // Sort the second array arr2
        Arrays.sort(arr2);

        // Iterate the array arr1
        for (int i = 0; i < M; i++) {

            // Apply binary search and
            // find the index of closest
            // element to arr1[i] in arr2
            int ind = binarySearch(arr1[i],
                                   arr2);

            // No element at previous index
            if (ind == 0) {

                ans[i] = arr2[ind] * arr2[ind + 1];
            }

            // No element at the next index
            else if (ind == N - 1) {

                ans[i] = arr2[ind] * arr2[ind - 1];
            }

            // Elements at the next and
            // previous indices are present
            else {

                // arr2[ind - 1] is closer
                // to arr1[i]
                if (Math.abs(arr2[ind - 1]
                             - arr1[i])
                    < Math.abs(arr2[ind + 1]
                               - arr1[i])) {

                    ans[i] = arr2[ind] * arr2[ind - 1];
                }
                else if (

                    // arr2[ind + 1] is
                    // closer to arr1[i]
                    Math.abs(arr2[ind - 1]
                             - arr1[i])
                    > Math.abs(arr2[ind + 1]
                               - arr1[i])) {

                    ans[i] = arr2[ind] * arr2[ind + 1];
                }

                // If both arr2[ind - 1] and
                // arr2[ind + 1] are
                // equidistant from arr1[i]
                else {

                    ans[i] = Math.max(
                        arr2[ind] * arr2[ind - 1],
                        arr2[ind] * arr2[ind + 1]);
                }
            }
        }

        // Return the resulting array
        return ans;
    }

    // Binary search function to
    // find element closest to arr1[i]
    public static int binarySearch(int num,
                                   int[] arr)
    {

        // Initialize left right and mid
        int mid = -1, left = 0,
            right = arr.length - 1;

        // Initialize closest index and
        // smallest difference
        int closestInd = -1;
        int smallestDiff = Integer.MAX_VALUE;

        while (left <= right) {

            mid = (left + right) >> 1;

            if (Math.abs(arr[mid] - num)
                < smallestDiff) {

                // Update smallest difference
                smallestDiff = Math.abs(arr[mid] - num);

                // Update closest index

                closestInd = mid;
            }
            else if (Math.abs(arr[mid] - num)
                     == smallestDiff) {
                if (arr[mid] > arr[closestInd])
                    closestInd = mid;
            }

            if (arr[mid] == num) {

                // This is the closest
                // element index
                return mid;
            }
            else if (arr[mid] < num) {

                // Closer element lies
                // to the right
                left = mid + 1;
            }
            else {

                // Closer element lies
                // to the left
                right = mid - 1;
            }
        }

        return closestInd;
    }

    // Driver function
    public static void main(String[] args)
    {

        // Initialize the arrays
        int[] arr1 = { 5, 10, 17, 22, -1 };
        int[] arr2 = { -1, 26, 5, 20,
                       14, 17, -7 };

        // Call the function
        int[] res = maxProdClosest(arr1,
                                   arr2);

        // Iterate the array and
        // print the result
        for (int i = 0; i < res.length; i++) {
            System.out.print(res[i] + " ");
        }
    }
}