[20250820] BOJ / G4 / 가운데에서 만나기 / 한종욱

Author: Ukj0ng

Ukj0ng/202508/20 BOJ G4 가운데에서 만나기.md

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+```
+import java.io.*;
+import java.util.*;
+
+public class Main {
+    private static final BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
+    private static final BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(System.out));
+    private static List<Edge>[] graph;
+    private static List<Integer> answer;
+    private static int[][] dist;
+    private static int[] arr;
+    private static int N, M, K, min;
+    public static void main(String[] args) throws IOException {
+        init();
+        for (int i = 1; i <= N; i++) {
+            dijkstra(i);
+        }
+
+        for (int i = 1; i <= N; i++) {
+            int max = 0;
+            for (int idx = 1; idx <= K; idx++) {
+                int j = arr[idx];
+                max = Math.max(max, dist[j][i] + dist[i][j]);
+            }
+
+            if (max == min) {
+                answer.add(i);
+            } else if (max < min) {
+                min = max;
+                answer.clear();
+                answer.add(i);
+            }
+        }
+
+        Collections.sort(answer);
+
+        for (int element : answer) {
+            bw.write(element + " ");
+        }
+        bw.flush();
+        bw.close();
+        br.close();
+    }
+
+    private static void init() throws IOException {
+        StringTokenizer st = new StringTokenizer(br.readLine());
+        N = Integer.parseInt(st.nextToken());
+        M = Integer.parseInt(st.nextToken());
+
+        graph = new List[N + 1];
+        answer = new ArrayList<>();
+
+        for (int i = 1; i <= N; i++) {
+            graph[i] = new ArrayList<>();
+        }
+
+        for (int i = 1; i <= M; i++) {
+            st = new StringTokenizer(br.readLine());
+            int v = Integer.parseInt(st.nextToken());
+            int u = Integer.parseInt(st.nextToken());
+            int w = Integer.parseInt(st.nextToken());
+
+            graph[v].add(new Edge(u, w));
+        }
+
+        K = Integer.parseInt(br.readLine());
+        arr = new int[K + 1];
+        dist = new int[N + 1][N + 1];
+        st = new  StringTokenizer(br.readLine());
+        for (int i = 1; i <= K; i++) {
+            arr[i] = Integer.parseInt(st.nextToken());
+        }
+        min = Integer.MAX_VALUE - 10;
+    }
+
+    private static void dijkstra(int start) {
+        PriorityQueue<Edge> pq = new PriorityQueue<>((o1, o2) -> Integer.compare(o1.cost ,o2.cost));
+        int[] temp = new int[N + 1];
+        Arrays.fill(temp, Integer.MAX_VALUE - 10);
+        temp[start] = 0;
+        pq.add(new Edge(start, 0));
+
+        while (!pq.isEmpty()) {
+            Edge current = pq.poll();
+
+            if (current.cost > temp[current.dest]) continue;
+
+            for (Edge next : graph[current.dest]) {
+                int nDest = next.dest;
+                int nCost = current.cost + next.cost;
+
+                if (nCost < temp[nDest]) {
+                    temp[nDest] = nCost;
+                    pq.add(new Edge(nDest, temp[nDest]));
+                }
+            }
+        }
+
+        for (int i = 1; i <= N; i++) {
+            dist[start][i] = temp[i];
+        }
+    }
+
+    static class Edge {
+        int dest;
+        int cost;
+        Edge(int dest, int cost) {
+            this.dest = dest;
+            this.cost = cost;
+        }
+    }
+}
+
+```