[20250903] BOJ / G5 / 최소비용 구하기 / 이인희

LiiNi-coder/202509/03 BOJ 최소비용 구하기.md

@@ -0,0 +1,74 @@
+```java
+import java.io.BufferedReader;
+import java.io.IOException;
+import java.io.InputStreamReader;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.List;
+import java.util.PriorityQueue;
+import java.util.StringTokenizer;
+
+public class Main {
+    private static BufferedReader br;
+    private static int n;
+    private static int m;
+    private static List<Node>[] graph;
+    private static int[] dist;
+
+    private static class Node implements Comparable<Node> {
+        int v;
+        int w;
+        public Node(int v, int w) {
+            this.v = v;
+            this.w = w;
+        }
+        @Override
+        public int compareTo(Node other) {
+            return this.w - other.w;
+        }
+    }
+
+    public static void main(String[] args) throws IOException {
+        br = new BufferedReader(new InputStreamReader(System.in));
+        n = Integer.parseInt(br.readLine());
+        m = Integer.parseInt(br.readLine());
+        graph = new ArrayList[n + 1];
+        for (int i = 1; i <= n; i++) {
+            graph[i] = new ArrayList<>();
+        }
+        for (int i = 0; i < m; i++) {
+            StringTokenizer st = new StringTokenizer(br.readLine());
+            int a = Integer.parseInt(st.nextToken());
+            int b = Integer.parseInt(st.nextToken());
+            int c = Integer.parseInt(st.nextToken());
+
+            graph[a].add(new Node(b, c));
+        }
+        StringTokenizer st = new StringTokenizer(br.readLine());
+        int start = Integer.parseInt(st.nextToken());
+        int end = Integer.parseInt(st.nextToken());
+        dist = new int[n + 1];
+        Arrays.fill(dist, Integer.MAX_VALUE);
+
+        dijkstra(start);
+
+        System.out.println(dist[end]);
+    }
+
+    private static void dijkstra(int start) {
+        PriorityQueue<Node> pq = new PriorityQueue<>();
+        dist[start] = 0;
+        pq.add(new Node(start, 0));
+        while (!pq.isEmpty()) {
+            Node now = pq.poll();
+            if (dist[now.v] < now.w) continue;
+            for (Node next : graph[now.v]) {
+                if (dist[next.v] > dist[now.v] + next.w) {
+                    dist[next.v] = dist[now.v] + next.w;
+                    pq.add(new Node(next.v, dist[next.v]));
+                }
+            }
+        }
+    }
+}
+```