첫 시도
- N,M이 500,000이기 때문에 단순 완탐으로는 시간초과
- 정렬된 arr를 이분탐색
- MlogN으로 해결 가능
해결
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import java.io.*;
import java.lang.reflect.Array;
import java.util.*;
public class Main {
static int N;
static int[] arr1;
public static void main(String[] ars) throws IOException {
BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
StringBuilder sb = new StringBuilder();
StringTokenizer st;
N = Integer.parseInt(br.readLine());
st = new StringTokenizer(br.readLine());
arr1 = new int[N];
for (int i = 0; i < N; i++) {
arr1[i] = Integer.parseInt(st.nextToken());
}
Arrays.sort(arr1);
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(binarySearch(num)+" ");
}
System.out.println(sb);
}
public static int binarySearch(int value) {
int first = 0;
int last = N - 1;
int mid = 0;
while (first <= last) {
mid = (first + last) / 2;
if (arr1[mid] == value) {
return 1;
}
if (arr1[mid] < value) {
first = mid + 1;
} else {
last = mid - 1;
}
}
return 0;
}
}