Assign Cookies

/*
 * Problem : Count happy children.
 * Input   : Two arrays.
 * Output  : The number of happy children.
 * Approach: Sort and match.
 * Time    : O(n log n + m log m)
 * Space   : O(n + m)
 * Java    : 8 or newer.
 */
import java.util.Scanner;

public class Main {
    // This method solves the task. It receives the input and returns the answer.
    static int solve(int[] a, int[] b) {
        // Step 1: Sort both arrays. Then we can match the smallest greed with the smallest cookie that is big enough.
        int[] greed = a.clone();
        int[] cookies = b.clone();
        java.util.Arrays.sort(greed);
        java.util.Arrays.sort(cookies);

        // Step 2: child = the next child that needs a cookie.
        int child = 0;

        // Step 3: Offer each cookie, from small to big, to the least greedy child who is still sad.
        for (int cookie : cookies) {
            if (child < greed.length && greed[child] <= cookie) {
                child++;
            }
        }
        return child;
    }

    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        int size = scanner.nextInt();
        int[] a = new int[size];
        for (int i = 0; i < size; i++) {
            a[i] = scanner.nextInt();
        }
        int sizeB = scanner.nextInt();
        int[] b = new int[sizeB];
        for (int i = 0; i < sizeB; i++) {
            b[i] = scanner.nextInt();
        }
        System.out.println(solve(a, b));
    }
}