diff --git "a/03do-new30/202507/11 BOJ G3 \355\214\214\355\213\260.md" "b/03do-new30/202507/11 BOJ G3 \355\214\214\355\213\260.md" new file mode 100644 index 00000000..2ce54196 --- /dev/null +++ "b/03do-new30/202507/11 BOJ G3 \355\214\214\355\213\260.md" @@ -0,0 +1,67 @@ +```java +import java.io.*; +import java.util.*; + + +public class Main { + static int N, M, X; + static int[][] arr, revArr; + + 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()); + X = Integer.parseInt(st.nextToken()); + + arr = new int[N+1][N+1]; // 정방향 (a->b) + revArr = new int[N+1][N+1]; // 역방향 (a<-b) + for (int i = 0; i < M; i++) { + st = new StringTokenizer(br.readLine()); + int a = Integer.parseInt(st.nextToken()); + int b = Integer.parseInt(st.nextToken()); + int c = Integer.parseInt(st.nextToken()); + arr[a][b] = c; + revArr[b][a] = c; + } + + int[] fromX = dijkstra(X); + + arr = revArr; + int[] toX = dijkstra(X); + + int answer = 0; + for (int i = 1; i <= N; i++) { + answer = Math.max(answer, fromX[i] + toX[i]); + } + System.out.println(answer); + br.close(); + } + + private static int[] dijkstra(int start) { + int[] dist = new int[N+1]; + Arrays.fill(dist, Integer.MAX_VALUE); + dist[start] = 0; + PriorityQueue pq = new PriorityQueue<>(new Comparator() { + @Override + public int compare(int[] o1, int[] o2) { + return Integer.compare(o1[0], o2[0]); + } + }); + pq.offer(new int[] {0, start}); // (cost, node) + while (!pq.isEmpty()) { + int[] info = pq.poll(); + int node = info[1]; + for (int nextNode = 1; nextNode <= N; nextNode++) { + if (arr[node][nextNode] == 0) continue; + int newDist = dist[node] + arr[node][nextNode]; + if (dist[nextNode] > newDist) { + dist[nextNode] = newDist; + pq.offer(new int[] {newDist, nextNode}); + } + } + } + return dist; + } +} +```