BOJ_1916 : 최소비용 구하기 (다익스트라)

Author: spring0913

week7/BOJ_1916(최소비용 구하기).java

@@ -0,0 +1,57 @@
+import java.io.*;
+import java.util.*;
+
+public class Main {
+
+    public static int city;
+    public static List<List<int[]>> graph;
+    public static int[] dist;
+
+    public static void main(String[] args) throws IOException {
+        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
+        city = Integer.parseInt(br.readLine());
+        int bus = Integer.parseInt(br.readLine());
+        graph = new ArrayList<>();
+        dist = new int[city+1];
+        for(int i=0; i<=city; i++) {
+            graph.add(new ArrayList<>());
+            dist[i] = Integer.MAX_VALUE;
+        }
+        for(int i=0; i<bus; i++) {
+            StringTokenizer st = new StringTokenizer(br.readLine());
+            int v1 = Integer.parseInt(st.nextToken());
+            int v2 = Integer.parseInt(st.nextToken());
+            int cost = Integer.parseInt(st.nextToken());
+            graph.get(v1).add(new int[]{v2, cost});
+        }
+        StringTokenizer st = new StringTokenizer(br.readLine());
+        int start = Integer.parseInt(st.nextToken());
+        int end = Integer.parseInt(st.nextToken());
+        dijkstra(start, end);
+    }
+
+    public static void dijkstra(int start, int end) {
+        PriorityQueue<int[]> pq = new PriorityQueue<>((o1, o2) -> Integer.compare(o1[1], o2[1]));
+        pq.offer(new int[]{start, 0});
+        while(!pq.isEmpty()) {
+            int v = pq.peek()[0];
+            int cost = pq.peek()[1];
+            pq.poll();
+
+            if(dist[v] < cost) {
+                continue;
+            }
+
+            List<int[]> list = graph.get(v);
+            for(int i=0; i<list.size(); i++) {
+                int nextV = list.get(i)[0];
+                int nextCost = list.get(i)[1];
+                if(dist[nextV] > cost + nextCost) {
+                    dist[nextV] = cost + nextCost;
+                    pq.offer(new int[]{nextV, dist[nextV]});
+                }
+            }
+        }
+        System.out.println(dist[end]);
+    }
+}