[20250801] BOJ / G5 / 집합의 표현 / 이인희

LiiNi-coder/202508/01 BOJ 집합의 표현.md

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+```java
+import java.io.BufferedReader;
+import java.io.IOException;
+import java.io.InputStreamReader;
+import java.util.Iterator;
+import java.util.StringTokenizer;
+
+public class Main {
+	private static class WeightedUF{
+		int[] ids;
+		int[] size;
+		public WeightedUF(int v) {
+			ids = new int[v];
+			size = new int[v];
+			for (int i = 0; i < ids.length; i++) {
+				ids[i] = i;
+				size[i] = 1;
+			}
+		}
+		public int root(int a) {
+			while(a != ids[a])
+				a = ids[a];
+			return a;
+		}
+		public void union(int a, int b) {
+			int g, l;
+			if(size[a] >= size[b]) {
+				g = a;
+				l = b;
+			}else {
+				l = a;
+				g = b;
+			}
+			// b가 더 깊이가 짧음
+			ids[root(b)] = root(a);
+		}
+		public boolean connected(int a, int b) {
+			return root(a) == root(b);
+		}
+	}
+	private static BufferedReader br;
+	private static Main.WeightedUF uf;
+	private static int m;
+	private static int n;
+	public static void main(String[] args) throws IOException {
+		br = new BufferedReader(new InputStreamReader(System.in));
+        StringBuilder sb = new StringBuilder();
+		String[] temp = br.readLine().split(" ");
+		n = Integer.parseInt(temp[0])+1;
+		m = Integer.parseInt(temp[1]);
+		uf = new WeightedUF(n);
+
+		for(int i = 0; i<m; i++) {
+			StringTokenizer st = new StringTokenizer(br.readLine());
+			int command = Integer.parseInt( st.nextToken());
+			int a = Integer.parseInt(st.nextToken());
+			int b = Integer.parseInt(st.nextToken());
+			if(command == 0) {
+				// 합집합
+				uf.union(a, b);
+			}else {
+				// conneted()
+				if(uf.connected(a, b))
+					sb.append("YES\n");
+				else
+					sb.append("NO\n");
+			}
+		}
+		System.out.println(sb.toString());
+		br.close();
+	}
+
+
+}
+```