[백준/BOJ] 2776. 암기왕 [Silver 4]

2776. 암기왕
      문제출처 : https://www.acmicpc.net/problem/2776

이분 탐색

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.Arrays;
import java.util.StringTokenizer;

public class baekjoon2776 {
    public static int binarySearch(int[] arr,int start, int end, int target){
        while (start <= end) {
            int mid = (start + end) / 2;
            if (arr[mid] < target) {
                start = mid + 1;
            } else if (arr[mid] > target) {
                end = mid - 1;
            } else {
                return mid;
            }

        }
        return -1;
    }
    public static void main(String args[])throws IOException{
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        StringTokenizer st;
        int T = Integer.parseInt(br.readLine());
        while(T-- > 0){
            StringBuffer sb = new StringBuffer();

            int N = Integer.parseInt(br.readLine());

            int[] arr = new int[N];

            st = new StringTokenizer(br.readLine()," ");
            for(int i=0;i<N;i++){
                arr[i] = Integer.parseInt(st.nextToken());
            }

            Arrays.sort(arr);

            int M = Integer.parseInt(br.readLine());

            st = new StringTokenizer(br.readLine()," ");
            for(int i=0;i<M;i++){
                if(binarySearch(arr,0,N-1,Integer.parseInt(st.nextToken())) == -1){
                    if (i != M - 1) {
                        sb.append(0).append("\n");
                    } else {
                        sb.append(0);
                    }
                }else {
                    if (i != M - 1) {
                        sb.append(1).append("\n");
                    } else {
                        sb.append(1);
                    }
                }
            }
            System.out.println(sb);
        }
    }
}

집합 자료구조 활용

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.Arrays;
import java.util.HashSet;
import java.util.Set;
import java.util.StringTokenizer;

public class baekjoon2776 {
    static BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
    static StringTokenizer st;
    static StringBuilder sb;
    public static void main(String args[])throws IOException{
        int T = Integer.parseInt(br.readLine());
        
        while(T!=0){
            sb = new StringBuilder();
            Set<Integer> set = new HashSet<>();
            int N = Integer.parseInt(br.readLine());
            st = new StringTokenizer(br.readLine());
            for(int i=0;i<N;i++){
                set.add(Integer.parseInt(st.nextToken()));
            }
            int M = Integer.parseInt(br.readLine());
            st = new StringTokenizer(br.readLine());
            for(int i=0;i<M;i++){
                sb.append(set.contains(Integer.parseInt(st.nextToken()))? 1: 0).append("\n");
            }
            System.out.print(sb);
            T--;
        }
    }
}

List로도 풀고 다해봤는데, 어떻게 푸는지는 알겠는데, 백준 제출할때 계속 시간초과가 나서 다른 방법으로 풀었다.
시간제한만 안걸리면 괜찮은 문제같은데 시간제한도 턱걸이로 통과하니까 더어렵게 느껴지는것 같다.