[백준] 7795번 먹을 것인가 먹힐 것인가

import java.util.Arrays;
import java.util.Scanner;
public class Main {

    public static void main(String[] args) {
        Scanner kb = new Scanner(System.in);
        int T = kb.nextInt();

        for (int t = 0; t < T; t++) {
            int N = kb.nextInt();
            int M = kb.nextInt();

            int[] A = new int[N];
            int[] B = new int[M];

            for (int i = 0; i < N; i++) {
                A[i] = kb.nextInt();
            }

            for (int i = 0; i < M; i++) {
                B[i] = kb.nextInt();
            }

            Arrays.sort(B);

            int result = 0;

            for (int i = 0; i < N; i++) {
                result += binarySearch(B, A[i]);
            }

            System.out.println(result);
        }
    }

    static int binarySearch(int[] B, int x) {
        int left = 0;
        int right = B.length - 1;
        int count = 0;

        while (left <= right) {
            int mid = (left + right) / 2;

            if (B[mid] < x) {
                count = mid + 1;
                left = mid + 1;
            } else {
                right = mid - 1;
            }
        }

        return count;
    }
}