Merge pull request #62 from Jsumin07/feat/baekjoon

feat (Soomin): add/week8-Baekjoon_1167.java

Author: Jsumin07

Soomin/week8/Beakjoon_1167.java

@@ -0,0 +1,63 @@
+import java.io.*;
+import java.util.*;
+
+public class Beakjoon_1167 {
+    static int V;
+    static ArrayList<Edge>[] tree;
+    static boolean[] visited;
+    static int farthestNode;   
+    static int maxDistance;    
+
+    static class Edge {
+        int to;
+        int weight;
+        public Edge(int to, int weight) {
+            this.to = to;
+            this.weight = weight;
+        }
+    }
+
+    public static void main(String[] args) throws IOException {
+        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
+        V = Integer.parseInt(br.readLine().trim());
+        tree = new ArrayList[V + 1];
+        for (int i = 1; i <= V; i++) {
+            tree[i] = new ArrayList<>();
+        }
+
+        for (int i = 0; i < V; i++) {
+            StringTokenizer st = new StringTokenizer(br.readLine());
+            int from = Integer.parseInt(st.nextToken());
+            while (true) {
+                int to = Integer.parseInt(st.nextToken());
+                if (to == -1) break;
+                int w = Integer.parseInt(st.nextToken());
+                tree[from].add(new Edge(to, w));
+            }
+        }
+
+        visited = new boolean[V + 1];
+        visited[1] = true;
+        dfs(1, 0);
+
+        visited = new boolean[V + 1];
+        visited[farthestNode] = true;
+        maxDistance = 0;
+        dfs(farthestNode, 0);
+
+        System.out.println(maxDistance);
+    }
+
+    static void dfs(int cur, int dist) {
+        if (dist > maxDistance) {
+            maxDistance = dist;
+            farthestNode = cur;
+        }
+        for (Edge e : tree[cur]) {
+            if (!visited[e.to]) {
+                visited[e.to] = true;
+                dfs(e.to, dist + e.weight);
+            }
+        }
+    }
+}