diff --git "a/JHLEE325/202508/01 BOJ G4 \355\202\244 \354\210\234\354\204\234.md" "b/JHLEE325/202508/01 BOJ G4 \355\202\244 \354\210\234\354\204\234.md" new file mode 100644 index 00000000..cc20275f --- /dev/null +++ "b/JHLEE325/202508/01 BOJ G4 \355\202\244 \354\210\234\354\204\234.md" @@ -0,0 +1,49 @@ +```java +import java.io.*; +import java.util.*; + +public class Main { + + public static void main(String[] args) throws Exception { + BufferedReader br = new BufferedReader(new InputStreamReader(System.in)); + StringTokenizer st = new StringTokenizer(br.readLine()); + + int n = Integer.parseInt(st.nextToken()); + int m = Integer.parseInt(st.nextToken()); + boolean[][] arr = new boolean[n][n]; + + for (int i = 0; i < m; i++) { + st = new StringTokenizer(br.readLine()); + int a = Integer.parseInt(st.nextToken()) - 1; + int b = Integer.parseInt(st.nextToken()) - 1; + arr[a][b] = true; + } + + for (int k = 0; k < n; k++) { + for (int i = 0; i < n; i++) { + for (int j = 0; j < n; j++) { + if (arr[i][k] && arr[k][j]) + arr[i][j] = true; + } + } + } + + int cnt = 0; + for (int i = 0; i < n; i++) { + boolean isknow = true; + for (int j = 0; j < n; j++) { + if (i == j) + continue; + if (!arr[i][j] && !arr[j][i]) + isknow = false; + } + if (isknow) + cnt++; + } + + System.out.println(cnt); + } + +} + +```