[20251217] BOJ / G4 / 타임머신 / 한종욱

Ukj0ng/202512/17 BOJ G4 타임머신.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 final long INF = (long)3e10 + 5;
+    private static List<int[]> edges;
+    private static long[] dist;
+    private static int N, M;
+
+    public static void main(String[] args) throws IOException {
+        init();
+        boolean result = bellmanFord();
+
+        if (result) bw.write(-1 + "\n");
+        else {
+            for (int i = 2; i <= N; i++) {
+                if (dist[i] != INF) bw.write(dist[i] + "\n");
+                else bw.write(-1 + "\n");
+            }
+        }
+        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());
+        edges = new ArrayList<>();
+        dist = new long[N+1];
+
+        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());
+            edges.add(new int[]{A, B, C});
+        }
+    }
+
+    private static boolean bellmanFord() {
+        Arrays.fill(dist, INF);
+        dist[1] = 0;
+
+        for (int i = 0; i < N-1; i++) {
+            for (int[] edge : edges) {
+                if (dist[edge[0]] != INF && dist[edge[1]] > dist[edge[0]] + edge[2]) {
+                    dist[edge[1]] = dist[edge[0]] + edge[2];
+                }
+            }
+        }
+
+        for (int[] edge : edges) {
+            if (dist[edge[0]] != INF && dist[edge[1]] > dist[edge[0]] + edge[2]) {
+                return true;
+            }
+        }
+
+        return false;
+    }
+}
+```