[20250810] BOJ / G4 / 운동 / 이인희

LiiNi-coder/202508/10 BOJ 운동.md

@@ -0,0 +1,72 @@
+```java
+import java.io.*;
+import java.util.*;
+
+public class Main {
+    static class Edge {
+        int to;
+        int cost;
+        Edge(int to, int cost) {
+            this.to = to;
+            this.cost = cost;
+        }
+    }
+
+    private static final int INF = 1_000_000_000;//플루이드워셜은 오버플로우 방지
+    private static int V
+    private static int E;
+    private static ArrayList<Edge>[] graph;
+    private static int[][] dist;
+
+    public static void main(String[] args) throws IOException {
+        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
+        StringTokenizer st = new StringTokenizer(br.readLine());
+        V = Integer.parseInt(st.nextToken());
+        E = Integer.parseInt(st.nextToken());
+        graph = new ArrayList[V + 1];
+        for (int i = 1; i <= V; i++) {
+            graph[i] = new ArrayList<>();
+        }
+
+        dist = new int[V + 1][V + 1];
+        for (int i = 1; i <= V; i++) {
+            Arrays.fill(dist[i], INF);
+            dist[i][i] = 0;
+        }
+
+        for (int i = 0; i < E; i++) {
+            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 Edge(b, c));
+            dist[a][b] = c;
+        }
+
+        //플로이드워셜진행
+        for (int k = 1; k <= V; k++) {
+            for (int i = 1; i <= V; i++) {
+                for (int j = 1; j <= V; j++) {
+                    if (dist[i][j] > dist[i][k] + dist[k][j]) {
+                        dist[i][j] = dist[i][k] +dist[k][j];
+                    }
+                }
+            }
+        }
+
+        //최소 사이클 찾기
+        int answer = INF;
+        for (int a = 1; a <= V; a++) {
+            for (int b = 1; b <= V; b++) {
+                if (a == b) continue;
+                if (dist[a][b] != INF && dist[b][a] != INF) {
+                    answer = Math.min(answer, dist[a][b] + dist[b][a]);
+                }
+            }
+        }
+
+        System.out.println((answer == INF)? -1 : answer);
+        br.close();
+    }
+}
+```