백준[JAVA] 1920.수 찾기 - 자바

📖 문제

📃 코드

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

public class Main {
    public static int[] arr;

    public static void main(String[] args) throws IOException {
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));

        int N = Integer.parseInt(br.readLine());
        arr = new int[N];

        StringTokenizer st = new StringTokenizer(br.readLine(), " ");
        for (int i = 0; i < N; i++) {
            arr[i] = Integer.parseInt(st.nextToken());
        }
        // Vital condition of binarySearch
        Arrays.sort(arr);

        int M = Integer.parseInt(br.readLine());
        st = new StringTokenizer(br.readLine(), " ");

        StringBuilder sb = new StringBuilder();
        for (int i = 0; i < M; i++) {
            if (binarySearch(Integer.parseInt(st.nextToken()))) {
                sb.append(1).append('\n');
            } else {
                sb.append(0).append('\n');
            }
        }
        System.out.println(sb);
    }

    public static boolean binarySearch(int key) {
        int start = 0;
        int end = arr.length - 1;

        while (end >= start) {
            int half = (start + end) / 2;
            if (key > arr[half]) {
                start = half + 1;
            } else if (key < arr[half]) {
                end = half - 1;
            } else if (key == arr[half]) {
                return true;
            }
        }
        return false;
    }
}

 

🔗 링크

https://www.acmicpc.net/problem/1920

1920번: 수 찾기