[20260326] BOJ / G5 / 귀찮은 해강이 / 이인희

Author: LiiNi-coder

LiiNi-coder/202603/26 BOJ 귀찮은 해강이.md

@@ -0,0 +1,78 @@
+```java
+import java.util.*;
+import java.io.*;
+
+public class Main{
+	static int N, M;
+	static int[] Order;
+	static class UF{
+		int[] roots;
+		int[] sizes;
+		UF(int n){
+			roots = new int[n];
+			sizes = new int[n];
+			for(int i = 0; i < n; i++){
+				roots[i] = i;
+				sizes[i] = 1;
+			}
+		}
+		int getRoot(int target){
+			while(true){
+				int temp = roots[target];
+				if(temp == target)
+					return temp;
+				target = temp;
+			}
+
+		}
+		void union(int a1, int a2){
+			int r1 = getRoot(a1);
+			int r2 = getRoot(a2);
+			if(r1 == r2) return;
+			if(sizes[r1] >= sizes[r2]){
+				roots[r2] = r1;
+				sizes[r1] += sizes[r2];
+			}else{
+				roots[r1] = r2;
+				sizes[r2] += sizes[r1];
+			}
+		}
+		boolean connected(int a1, int a2){
+			return getRoot(a1) == getRoot(a2);
+
+		}
+	}
+
+	public static void main(String[] args) throws IOException{
+		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
+		StringTokenizer st = new StringTokenizer(br.readLine());
+		N = Integer.parseInt(st.nextToken());
+		M = Integer.parseInt(st.nextToken());
+		Order = new int[N];
+		UF uf = new UF(N);
+		for(int m = 0; m < M; m++){
+			st = new StringTokenizer(br.readLine());
+			int a1 = Integer.parseInt(st.nextToken()) - 1;
+			int a2= Integer.parseInt(st.nextToken())-1;
+			uf.union(a1, a2);
+
+		}
+		st = new StringTokenizer(br.readLine());
+		int prev = Integer.parseInt(st.nextToken())-1;
+		int prevRoot = uf.getRoot(prev);
+		int answer = 0;
+		// System.out.println("DEBUG: ");
+		while(st.hasMoreTokens()){
+			// System.out.println("DEBUG: ");
+			int now = Integer.parseInt(st.nextToken())-1;
+			int nowRoot = uf.getRoot(now);
+			if(prevRoot != nowRoot)
+				answer++;
+			prev = now;
+			prevRoot = nowRoot;
+		}
+		System.out.println(answer);
+		br.close();
+	}
+}
+```