[백준] 숫자 카드 2 10816 - JAVA

문제

https://www.acmicpc.net/problem/10816

10816번: 숫자 카드 2

 

코드

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

public class Main {
	
	public static void main(String args[]) throws IOException{
		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
		StringTokenizer st;
		StringBuilder sb = new StringBuilder();
		
		int n = Integer.parseInt(br.readLine());
		
		int arr [] = new int[n];
		
		st = new StringTokenizer(br.readLine());
		for(int i=0;i<n;i++) {
			int num = Integer.parseInt(st.nextToken());
			
			arr[i] = num;
		}
		
		Arrays.sort(arr);
		
		int m = Integer.parseInt(br.readLine());
		
		st = new StringTokenizer(br.readLine());
		for(int i=0;i<m;i++) {
			int num = Integer.parseInt(st.nextToken());
			sb.append(upperbound(arr, num) - lowbound(arr, num) +" ");
		}
       
		System.out.print(sb);
   }
   
	static int upperbound(int [] arr, int key) {
		int l = 0;
		int r = arr.length;
		
		while(l<r) {
			int mid = (l+r)/2;
			if(key < arr[mid]) {
				r = mid;
			}
			else {
				l = mid+1;
			}
		}
		return l;
	}
	
	static int lowbound(int [] arr, int key) {
		int l = 0;
		int r = arr.length;
		while(l<r) {
			int mid = (l+r)/2;
			if(key <= arr[mid]) {
				r = mid;
			}
			else {
				l = mid+1;
			}
		}
		return l;
	}
   
}