网捷达

Given two arrays of equal size, an integer array a[] and a character array b[], each character is associated with an integer at the same index.

Sort the character array b[] according to the ascending order of the integer array a[].
The one-to-one correspondence between integers and characters must be preserved after sorting.

Example:

Input: a[] = {3, 1, 2}, b[] = {'G', 'E', 'K'}
Output: {'E', 'K', 'G'}
Explanation: After sorting the integer array a[] in ascending order as {1, 2, 3}, the characters in b[] are rearranged to match this order, resulting in {'E', 'K', 'G'}.

Approach

Follow these steps to sort the character array according to the integer array:

Define a Pair class containing an integer and its corresponding character.
Create an array of Pair objects for all elements in the arrays.
Sort the Pair array using the integer value as the key.
Extract the characters from the sorted Pair array and update the character array.

Java

import java.util.*;

// Class to store integer and corresponding character
class Pair {
    int num;
    char ch;

    Pair(int num, char ch)
    {
        this.num = num;
        this.ch = ch;
    }
}

public class SortCharByInt {

    // Function to sort character array according to integer
    // array
    static void sortCharByInt(int[] a, char[] b)
    {
        int n = a.length;
        Pair[] pairs = new Pair[n];

        // Store integer and character as pairs
        for (int i = 0; i < n; i++) {
            pairs[i] = new Pair(a[i], b[i]);
        }

        // Sort pairs based on integer values
        Arrays.sort(pairs,
                    Comparator.comparingInt(p -> p.num));

        // Update character array according to sorted pairs
        for (int i = 0; i < n; i++) {
            b[i] = pairs[i].ch;
        }
    }

    public static void main(String[] args)
    {
        int[] a = { 3, 1, 2 };
        char[] b = { 'G', 'E', 'K' };

        sortCharByInt(a, b);

        System.out.println("Sorted character array: "
                           + Arrays.toString(b));
    }
}

Output

Sorted character array: [E, K, G]

Time Complexity: O(n log n)
Space Complexity: O(n)

Note: The sorting order can be either ascending or descending based on the problem requirement or user’s choice.

Sort an Array According to Another Array in Java

Approach

Explore