알고리즘 풀이/백준

[백준][Java] 1920번 수 찾기 (이진탐색)

배게 2021. 10. 14. 05:26
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import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;
import java.util.Arrays;
 
 
 
public class Main {
        
    private static BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
    private static BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(System.out));
    
    public static boolean isExist(int[] numArr, int X) {
        int left = 0;
        int right = numArr.length-1;
        int mid = 0;
        
        while(left<=right) {
            mid = (left+right)/2;
            if(numArr[mid]<X)
                left = mid+1;
            else if(numArr[mid]>X)
                right = mid-1;
            else 
                return true;
        }
        
        return false;
    }
    
    public static void main(String[] args) throws IOException{
        int N = stoi(br.readLine());
        int[] numArr = new int[N];
        String[] str = br.readLine().split(" ");
        for(int i=0; i<N; i++)
            numArr[i] = stoi(str[i]);
        Arrays.sort(numArr);
        
        int M = stoi(br.readLine());
        str = br.readLine().split(" ");
        
        StringBuilder sb = new StringBuilder();
        for(int i=0; i<M; i++) {
            if( isExist(numArr, stoi(str[i])) )
                sb.append("1\n");
            else 
                sb.append("0\n");
        }
        
        System.out.println(sb.toString());
        
        
        
        
//        bw.write("");
//        bw.flush();
//        bw.close();
    }
 
    private static int stoi(String input) {
        return Integer.parseInt(input);
    }
}
cs