[BOJ][10815] 숫자 카드

1. 문제 링크

https://www.acmicpc.net/problem/10815

2. 사용 알고리즘

이분 탐색

3. 풀이

이분 탐색을 통해 보유여부 확인

4. 소스 코드

4-1. C++

https://github.com/dev-aiden/problem-solving/blob/main/boj/10815.cpp

#include <iostream>
#include <algorithm>

using namespace std;

int n, m;
int arr[500003], arr2[500003];

int bSearch(int num) {
    int start = 0, end = n - 1;
    while(start <= end) {
        int mid = (start + end) / 2;
        if(arr[mid] == num) {
            return 1;
        } else if(arr[mid] > num) {
            end = mid - 1;
        } else if(arr[mid] < num) {
            start = mid + 1;
        }
    }
    return 0;
}

int main(void) {
    ios_base::sync_with_stdio(false);
    cin.tie(NULL); cout.tie(NULL);
    cin >> n;
    for(int i = 0; i < n; ++i) cin >> arr[i];
    sort(arr, arr + n);
    cin >> m;
    for(int i = 0; i < m; ++i) cin >> arr2[i];
    for(int i = 0; i < m; ++i) cout << bSearch(arr2[i]) << " ";
    cout << "\n";
    return 0;
}

4-2. JAVA

https://github.com/dev-aiden/problem-solving/blob/main/boj/10815.java

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

public class Main {

    static int n, m;
    static int[] arr = new int[500003];
    static int[] arr2 = new int[500003];

    public static void main(String[] args) throws IOException {
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        n = Integer.parseInt(br.readLine());
        StringTokenizer st = new StringTokenizer(br.readLine());
        for(int i = 0; i < n; ++i) arr[i] = Integer.parseInt(st.nextToken());
        Arrays.sort(arr, 0, n);
        m = Integer.parseInt(br.readLine());
        st = new StringTokenizer(br.readLine());
        for(int i = 0; i < m; ++i) arr2[i] = Integer.parseInt(st.nextToken());
        StringBuilder sb = new StringBuilder();
        for(int i = 0; i < m; ++i) sb.append(bSearch(arr2[i])).append(" ");
        sb.append("\n");
        System.out.println(sb);
    }

    public static int bSearch(int num) {
        int start = 0, end = n - 1;
        while(start <= end) {
            int mid = (start + end) / 2;
            if(arr[mid] == num) {
                return 1;
            } else if(arr[mid] > num) {
                end = mid - 1;
            } else if(arr[mid] < num) {
                start = mid + 1;
            }
        }
        return 0;
    }
}