solve : 1717 집합의 표현

java/src/boj1717/Main.java

@@ -0,0 +1,63 @@
+package boj1717;
+
+import java.io.BufferedReader;
+import java.io.IOException;
+import java.io.InputStreamReader;
+
+public class Main {
+
+    private static final BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));
+
+    private static int[] parents;
+
+    public static void main(String[] args) {
+        String[] nm = readLine().split(" ");
+        int n = Integer.parseInt(nm[0]);
+        int m = Integer.parseInt(nm[1]);
+
+        parents = new int[n + 1];
+        for (int i = 0; i < n + 1; i++) {
+            parents[i] = i;
+        }
+
+        while (m-- > 0) {
+            String[] line = readLine().split(" ");
+            int command = Integer.parseInt(line[0]);
+            int x = Integer.parseInt(line[1]);
+            int y = Integer.parseInt(line[2]);
+
+            if (command == 0) {
+                union(x, y);
+            } else if (command == 1) {
+                if (find(x) == find(y)) {
+                    System.out.println("YES");
+                } else {
+                    System.out.println("NO");
+                }
+            }
+        }
+    }
+
+    private static void union(int x, int y) {
+        int rootX = find(x);
+        int rootY = find(y);
+        if (rootX != rootY) {
+            parents[rootY] = parents[rootX];
+        }
+    }
+
+    private static int find(int x) {
+        if (parents[x] != x) {
+            parents[x] = find(parents[x]);
+        }
+        return parents[x];
+    }
+
+    private static String readLine() {
+        try {
+            return reader.readLine();
+        } catch (IOException e) {
+            throw new RuntimeException(e);
+        }
+    }
+}