[20250903] BOJ / G1 / K-지폐 / 한종욱

Author: Ukj0ng

Ukj0ng/202509/3 BOJ G1 K-지폐.md

@@ -0,0 +1,99 @@
+```
+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) 1e15 + 10;
+    private static List<Edge>[] graph;
+    private static long[][] dist;
+    private static int N, M, K, S, T;
+
+    public static void main(String[] args) throws IOException {
+        init();
+        dijkstra(S);
+
+        long answer = -1;
+        if (dist[T][0] != INF) {
+            answer = dist[T][0];
+        }
+
+        if (answer == -1) bw.write("IMPOSSIBLE" + "\n");
+        else bw.write(answer + "\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());
+        K = Integer.parseInt(st.nextToken());
+
+        st = new StringTokenizer(br.readLine());
+        S = Integer.parseInt(st.nextToken());
+        T = Integer.parseInt(st.nextToken());
+
+        graph = new List[N + 1];
+        dist = new long[N + 1][K];
+
+        for (int i = 1; i <= N; i++) {
+            graph[i] = new ArrayList<>();
+        }
+
+        for (int i = 0; i < M; i++) {
+            st = new StringTokenizer(br.readLine());
+            int a = Integer.parseInt(st.nextToken());
+            int b = Integer.parseInt(st.nextToken());
+            long cost = Long.parseLong(st.nextToken());
+
+            graph[a].add(new Edge(b, cost));
+        }
+    }
+
+    private static void dijkstra(int start) {
+        PriorityQueue<Edge> pq = new PriorityQueue<>((o1, o2) -> Long.compare(o1.cost, o2.cost));
+        for (int i = 1; i <= N; i++) {
+            Arrays.fill(dist[i], INF);
+        }
+        dist[start][0] = 0;
+        pq.add(new Edge(start, 0, 0));
+
+        while (!pq.isEmpty()) {
+            Edge current = pq.poll();
+
+            if (current.cost > dist[current.dest][current.state]) continue;
+
+            for (Edge next : graph[current.dest]) {
+                long nCost = current.cost + next.cost;
+                int nState = (int) (nCost % K);
+
+                if (nCost < dist[next.dest][nState]) {
+                    dist[next.dest][nState] = nCost;
+                    pq.add(new Edge(next.dest, dist[next.dest][nState], nState));
+                }
+            }
+        }
+    }
+
+    static class Edge {
+        int dest;
+        long cost;
+        int state;
+
+        public Edge(int dest, long cost, int state) {
+            this.dest = dest;
+            this.cost = cost;
+            this.state = state;
+        }
+
+        public Edge(int dest, long cost) {
+            this.dest = dest;
+            this.cost = cost;
+            this.state = 0;
+        }
+    }
+}
+```