[20250903] BOJ / G1 / 인터넷 설치 / 이종환

0224LJH/202509/03 BOJ 인터넷 설치

@@ -0,0 +1,161 @@
+```java
+import java.io.IOException;
+import java.io.*;
+import java.util.*;
+
+
+public class Main {
+
+
+	static Node[] nodes;
+	static boolean[] visited;
+	static int[] totalCost;
+
+	static boolean canReach = false;
+	static int nodeCnt, edgeCnt, freeCnt,ans;
+
+	static PriorityQueue<Node> nodePq = new PriorityQueue<>();;
+
+	static class Node implements Comparable<Node>{
+		int num;
+		HashMap<Integer,Integer> to = new HashMap<>();
+
+		public void addEdge(int nodeNum, int cost) {
+			Node n = nodes[nodeNum];
+
+			if (!to.containsKey(nodeNum)) {
+				to.put(nodeNum, cost);
+				n.to.put(num, cost);
+				return;
+			}
+
+			if (to.get(nodeNum) > cost) {
+				to.replace(nodeNum, cost);
+				n.to.replace(num, cost);
+			}
+		}
+
+		public Node(int num) {
+			this.num = num;
+		}
+
+		@Override
+		public int compareTo(Node o) {
+
+			return Integer.compare(totalCost[this.num], totalCost[o.num]);
+		}
+	}
+
+
+	public static void main(String[] args) throws IOException {
+		init();
+		process();
+		print();
+
+	}
+
+	public static void init() throws IOException {
+		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
+		StringTokenizer st = new StringTokenizer(br.readLine());
+
+		nodeCnt = Integer.parseInt(st.nextToken());
+		edgeCnt = Integer.parseInt(st.nextToken());
+		freeCnt = Integer.parseInt(st.nextToken());
+
+		nodes = new Node[nodeCnt+1];
+		visited = new boolean[nodeCnt+1];
+		totalCost = new int [nodeCnt+1];
+
+		for (int i = 1; i <= nodeCnt; i++) {
+			nodes[i] = new Node(i);
+		}
+
+		for (int i = 0; i < edgeCnt; i++) {
+			st = new StringTokenizer(br.readLine());
+			int num1 = Integer.parseInt(st.nextToken());
+			int num2 = Integer.parseInt(st.nextToken());
+			int cost = Integer.parseInt(st.nextToken());
+
+			nodes[num1].addEdge(num2, cost);
+		}
+
+
+	}
+
+	public static void process() throws IOException {
+
+
+		int start = 0;
+		int end = 1000000;
+
+		int mid = (start+end)/2;
+
+		int lowestSuccess = Integer.MAX_VALUE;
+
+		while(start < end) {
+			canReach = false;
+			djikstra(mid);
+			System.out.println(mid);
+			if (canReach) {
+				end = mid;
+
+				lowestSuccess = Math.min(mid,lowestSuccess);
+			}
+			else start = mid+1;
+
+			mid = (start+end)/2;
+
+
+		}
+
+		if (lowestSuccess == Integer.MAX_VALUE) {
+			ans = -1;
+		} else ans = lowestSuccess;
+
+	}
+
+
+
+
+
+
+	private static void djikstra(int limit) {
+		Arrays.fill(totalCost, Integer.MAX_VALUE/2);
+		Arrays.fill(visited, false);
+		totalCost[1] = 0;
+		nodePq.add(nodes[1]);
+
+
+		while(!nodePq.isEmpty()) {
+			Node node = nodePq.poll();
+			if (visited[node.num]) continue;
+
+			visited[node.num] = true;
+
+			for (int n: node.to.keySet()) {
+				int cost = node.to.get(n);
+
+				int temp = totalCost[node.num];
+				if (cost > limit) temp++;
+
+				if (temp > freeCnt) continue;
+
+				if (totalCost[n] > temp) {
+					totalCost[n] = temp;
+					nodePq.add(nodes[n]);
+				}
+ 			}
+
+
+		}
+
+		if (totalCost[nodeCnt] != Integer.MAX_VALUE/2)  canReach = true;
+
+	}
+
+	public static void print() {
+		System.out.println(ans);
+	}
+}
+
+```