diff --git "a/ksinji/202601/24 BOJ \352\261\260\354\247\223\353\247\220.md" "b/ksinji/202601/24 BOJ \352\261\260\354\247\223\353\247\220.md" new file mode 100644 index 00000000..4922383b --- /dev/null +++ "b/ksinji/202601/24 BOJ \352\261\260\354\247\223\353\247\220.md" @@ -0,0 +1,83 @@ +```java +import java.io.*; +import java.util.*; + +public class Main { + static int n, m; + static int[] parent; + + public static void main(String[] args) throws Exception { + BufferedReader br = new BufferedReader(new InputStreamReader(System.in)); + StringTokenizer st = new StringTokenizer(br.readLine()); + + n = Integer.parseInt(st.nextToken()); + m = Integer.parseInt(st.nextToken()); + + parent = new int[n + 1]; + for (int i = 1; i <= n; i++) parent[i] = i; + + st = new StringTokenizer(br.readLine()); + int truthCnt = Integer.parseInt(st.nextToken()); + int[] truth = new int[truthCnt]; + for (int i = 0; i < truthCnt; i++) { + truth[i] = Integer.parseInt(st.nextToken()); + } + + if (truthCnt == 0) { + for (int i = 0; i < m; i++) { + br.readLine(); + } + System.out.println(m); + return; + } + + for (int i = 1; i < truthCnt; i++) { + union(truth[0], truth[i]); + } + + int[][] party = new int[m][]; + for (int i = 0; i < m; i++) { + st = new StringTokenizer(br.readLine()); + int k = Integer.parseInt(st.nextToken()); + int[] member = new int[k]; + for (int j = 0; j < k; j++) { + member[j] = Integer.parseInt(st.nextToken()); + } + party[i] = member; + + for (int j = 1; j < k; j++) { + union(member[0], member[j]); + } + } + + int truthGroup = find(truth[0]); + int ans = 0; + + for (int i = 0; i < m; i++) { + boolean ok = true; + for (int person : party[i]) { + if (find(person) == truthGroup) { + ok = false; + break; + } + } + if (ok) ans++; + } + + System.out.println(ans); + } + + static int find(int x) { + if (parent[x] == x) return x; + return parent[x] = find(parent[x]); + } + + static void union(int a, int b) { + a = find(a); + b = find(b); + if (a == b) return; + parent[b] = a; + } +} + +```