[20250627] BOJ / P5 / 쇼핑몰 / 권혁준

Author: oncsr

khj20006/202506/27 BOJ P5 쇼핑몰.md

@@ -0,0 +1,121 @@
+```java
+import java.util.*;
+import java.io.*;
+
+class IOController {
+    BufferedReader br;
+    BufferedWriter bw;
+    StringTokenizer st;
+
+    public IOController() {
+        br = new BufferedReader(new InputStreamReader(System.in));
+        bw = new BufferedWriter(new OutputStreamWriter(System.out));
+        st = new StringTokenizer("");
+    }
+
+    String nextLine() throws Exception {
+        String line = br.readLine();
+        st = new StringTokenizer(line);
+        return line;
+    }
+
+    String nextToken() throws Exception {
+        while (!st.hasMoreTokens()) nextLine();
+        return st.nextToken();
+    }
+
+    int nextInt() throws Exception {
+        return Integer.parseInt(nextToken());
+    }
+
+    long nextLong() throws Exception {
+        return Long.parseLong(nextToken());
+    }
+
+    double nextDouble() throws Exception {
+        return Double.parseDouble(nextToken());
+    }
+
+    void close() throws Exception {
+        bw.flush();
+        bw.close();
+    }
+
+    void write(String content) throws Exception {
+        bw.write(content);
+    }
+
+}
+
+public class Main {
+
+    static IOController io;
+
+    //
+
+    static int N, M, K;
+    static List<int[]>[] V;
+
+    public static void main(String[] args) throws Exception {
+
+        io = new IOController();
+
+        init();
+        solve();
+
+        io.close();
+
+    }
+
+    public static void init() throws Exception {
+
+        N = io.nextInt();
+        M = io.nextInt();
+        K = io.nextInt();
+        V = new List[N+1];
+        for(int i=1;i<=N;i++) V[i] = new ArrayList<>();
+        for(int i=0;i<M;i++) {
+            int a = io.nextInt(), b = io.nextInt(), c = io.nextInt();
+            V[a].add(new int[]{b,c});
+            V[b].add(new int[]{a,c});
+        }
+
+    }
+
+    static void solve() throws Exception {
+
+        int[] D = new int[N+1];
+        Arrays.fill(D, (int)1e9);
+        PriorityQueue<int[]> Q = new PriorityQueue<>((a,b) -> a[0]-b[0]);
+        for(int i=0;i<K;i++) {
+            int a = io.nextInt();
+            D[a] = 0;
+            Q.offer(new int[]{0,a});
+        }
+
+        while(!Q.isEmpty()) {
+            int[] now = Q.poll();
+            int d = now[0], n = now[1];
+            if(d > D[n]) continue;
+            for(int[] e:V[n]) {
+                int i = e[0], c = e[1];
+                if(D[i] > d+c) {
+                    D[i] = d+c;
+                    Q.offer(new int[]{D[i],i});
+                }
+            }
+        }
+
+        int ans = 0;
+        for(int n=1;n<=N;n++) for(int[] e:V[n]) {
+            int i = e[0], c = e[1];
+            if(D[n] + c == D[i]) continue;
+            ans = Math.max(Math.max(ans, D[n]*2), Math.max(D[i]*2, (D[n]+D[i]+c)));
+        }
+
+        io.write((ans+1)/2 + "\n");
+
+    }
+
+}
+```