[20250902] BOJ / G3 / 나만 안되는 연애 / 이인희

Author: LiiNi-coder

LiiNi-coder/202509/02 BOJ 나만 안되는 연애.md

@@ -0,0 +1,90 @@
+```java
+import java.io.BufferedReader;
+import java.io.IOException;
+import java.io.InputStreamReader;
+import java.util.ArrayList;
+import java.util.PriorityQueue;
+import java.util.StringTokenizer;
+
+public class Main {
+    private static BufferedReader br;
+    private static int n;
+    private static int m;
+    private static char[] genders;
+    private static ArrayList<Edge>[] graph;
+
+    private static class Edge implements Comparable<Edge> {
+        int v;
+        int w;
+        public Edge(int v, int w) {
+            this.v = v;
+            this.w = w;
+        }
+        @Override
+        public int compareTo(Edge o) {
+            return this.w - o.w;
+        }
+    }
+
+    public static void main(String[] args) throws IOException {
+        br = new BufferedReader(new InputStreamReader(System.in));
+        StringTokenizer st = new StringTokenizer(br.readLine());
+        n = Integer.parseInt(st.nextToken());
+        m = Integer.parseInt(st.nextToken());
+        genders = new char[n + 1];
+        st = new StringTokenizer(br.readLine());
+        for (int i = 1; i <= n; i++) {
+            genders[i] = st.nextToken().charAt(0);
+        }
+        graph = new ArrayList[n + 1];
+        for (int i = 1; i <= n; i++) {
+            graph[i] = new ArrayList<>();
+        }
+        for (int i = 0; i < m; i++) {
+            st = new StringTokenizer(br.readLine());
+            int u = Integer.parseInt(st.nextToken());
+            int v = Integer.parseInt(st.nextToken());
+            int w = Integer.parseInt(st.nextToken());
+            //같은 성별 노드는 연결하지 않음
+            if (genders[u] == genders[v]) continue;
+            graph[u].add(new Edge(v, w));
+            graph[v].add(new Edge(u, w));
+        }
+
+        int answer = prim();
+        System.out.println(answer);
+    }
+
+    private static int prim() {
+        boolean[] visited = new boolean[n + 1];
+        PriorityQueue<Edge> pq = new PriorityQueue<>();
+        int total = 0;
+        int count = 0;
+        visited[1] = true;
+        count++;
+        for (Edge e : graph[1]) {
+            pq.add(e);
+        }
+
+        while (!pq.isEmpty()) {
+            Edge cur = pq.poll();
+            if (visited[cur.v]) continue;
+            visited[cur.v] = true;
+            total += cur.w;
+            count++;
+            for (Edge next : graph[cur.v]) {
+                if (!visited[next.v]) {
+                    pq.add(next);
+                }
+            }
+        }
+
+        if (count == n) {
+            return total;
+        } else {
+            return -1;
+        }
+    }
+}
+
+```