1조 김지승 / 11월 1주차 / 목

jiseung/boj1197.java

@@ -0,0 +1,68 @@
+import java.util.*;
+import java.io.*;
+
+public class Main {
+
+	static class Edge implements Comparable<Edge> {
+		int num;
+		int w;
+
+		Edge(int num, int w) {
+			this.num = num;
+			this.w = w;
+		}
+
+		@Override
+		public int compareTo(Edge other) {
+			return Integer.compare(this.w, other.w);
+		}
+	}
+
+	public static void main(String[] args) throws IOException {
+		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
+		StringTokenizer st;
+
+		st = new StringTokenizer(br.readLine());
+
+		int V = Integer.parseInt(st.nextToken());
+		int E = Integer.parseInt(st.nextToken());
+
+		List<Edge>[] list = new ArrayList[V + 1];
+		boolean[] visited = new boolean[V + 1];
+
+		for(int i=1;i<=V;i++) {
+			list[i] = new ArrayList<>();
+		}
+
+		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 w = Integer.parseInt(st.nextToken());
+			list[a].add(new Edge(b, w));
+			list[b].add(new Edge(a, w));
+		}
+
+		PriorityQueue<Edge> pq = new PriorityQueue<>();
+
+		pq.add(new Edge(1, 0));
+		int result = 0;
+
+		while (!pq.isEmpty()) {
+			Edge now = pq.poll();
+			int num = now.num;
+			int w = now.w;
+
+			if(!visited[num]) {
+				visited[num]=true;
+				result +=w;
+				for(Edge next : list[num]) {
+					if(!visited[next.num]) {
+						pq.add(next);
+					}
+				}
+			}
+		}
+		System.out.println(result);
+	}
+}

jiseung/boj1647.java

@@ -0,0 +1,74 @@
+import java.util.*;
+import java.io.*;
+
+public class Main {
+
+    static class Node implements Comparable<Node> {
+        int end;
+        int w;
+
+        Node(int end, int w) {
+            this.end = end;
+            this.w = w;
+        }
+
+        @Override
+        public int compareTo(Node other) {
+            return Integer.compare(this.w, other.w);
+        }
+    }
+
+    public static void main(String[] args) throws IOException {
+        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
+        StringTokenizer st;
+
+        st = new StringTokenizer(br.readLine());
+
+        int N = Integer.parseInt(st.nextToken());
+        int M = Integer.parseInt(st.nextToken());
+
+        List<Node>[] list = new ArrayList[N + 1];
+        boolean[] visited = new boolean[N + 1];
+
+        for (int i = 0; i <= N; i++) {
+            list[i] = new ArrayList<>();
+        }
+
+
+        for (int i = 0; i < M; i++) {
+            st = new StringTokenizer(br.readLine());
+            int start = Integer.parseInt(st.nextToken());
+            int end = Integer.parseInt(st.nextToken());
+            int w = Integer.parseInt(st.nextToken());
+
+            list[start].add(new Node(end, w));
+            list[end].add(new Node(start, w));
+
+        }
+
+        PriorityQueue<Node> pq = new PriorityQueue<>();
+        pq.add(new Node(1, 0));
+
+        int result = 0;
+        int max = 0;
+        while (!pq.isEmpty()) {
+            Node now = pq.poll();
+            int end = now.end;
+            int w = now.w;
+
+            if (visited[end]) continue;
+
+            result += w;
+            max = Math.max(max, w);
+            visited[end] = true;
+
+            for (Node node : list[end]) {
+                if (!visited[node.end]) {
+                    pq.add(node);
+                }
+            }
+        }
+
+        System.out.println(result-max);
+    }
+}

jiseung/boj1774.java

@@ -0,0 +1,69 @@
+import java.util.*;
+import java.io.*;
+
+public class Main {
+	static int[] parent;
+	static int[][] god;
+    public static void main(String[] args) throws IOException {
+        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
+        StringTokenizer st;
+
+        st = new StringTokenizer(br.readLine());
+
+        int N = Integer.parseInt(st.nextToken());
+        int M = Integer.parseInt(st.nextToken());
+
+        god = new int[N+1][2];
+
+        for(int i=1;i<=N;i++) {
+        	st = new StringTokenizer(br.readLine());
+        	god[i][0] = Integer.parseInt(st.nextToken());
+        	god[i][1] = Integer.parseInt(st.nextToken());
+        }
+
+        parent = new int[N+1];
+        for(int i=1;i<=N;i++) {
+        	parent[i]=i;
+        }
+
+        for(int i=0;i<M;i++) {
+        	st = new StringTokenizer(br.readLine());
+        	int a = Integer.parseInt(st.nextToken());
+        	int b = Integer.parseInt(st.nextToken());
+        	union(a,b);
+        }
+
+        List<double[]> list = new ArrayList<>();
+        for(int i=1;i<N;i++) {
+        	for(int j = i+1;j<=N;j++) {
+        		list.add(new double[] {i,j,dist(i,j)});
+        	}
+        }
+        Collections.sort(list,(o1,o2)->o1[2]<o2[2]?-1:1);
+
+        double result=0;
+        for(int i=0;i<list.size();i++) {
+        	if(union((int)list.get(i)[0],(int)list.get(i)[1])) {
+        		result += list.get(i)[2];
+        	}
+        }
+        System.out.println(String.format("%.2f",result));
+
+    }
+    static int find(int a) {
+    	if(parent[a]==a) return a;
+    	return parent[a]=find(parent[a]);
+    }
+
+    static boolean union(int a, int b) {
+    	a = find(a);
+    	b = find(b);
+    	if(a==b) return false;
+    	if(a<b) parent[b]=a;
+    	else parent[a]=b;
+    	return true;
+    }
+    static double dist(int a, int b) {
+    	return Math.sqrt(Math.pow((god[a][0]-god[b][0]),2)+Math.pow((god[a][1]-god[b][1]),2));
+    }
+}