Merge pull request aerimforest#667 from aerimforest/hyeonjin

[Beakjoon] 22-12-31

Author: ramelHJ

Baekjoon/hyeonjin/두_수의_합.java

@@ -0,0 +1,32 @@
+import java.io.*;
+import java.util.*;
+
+public class Main {
+    public static void main(String[] args) throws Exception{
+        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
+        StringTokenizer str;
+
+        int N = Integer.valueOf(br.readLine());
+        int[] arr = new int[N];
+        str = new StringTokenizer(br.readLine());
+        for(int i = 0; i < N; i++){
+            arr[i] = Integer.valueOf(str.nextToken());
+        }
+        int X = Integer.valueOf(br.readLine());
+
+        Arrays.sort(arr);
+
+        int result = 0;
+        int left = 0;
+        int right = N - 1;
+        while(left < right){
+            int num = arr[left] + arr[right];
+            if(num == X) result++;
+
+            if(num < X) left++;
+            else right--;
+        }
+
+        System.out.println(result);
+    }
+}

Baekjoon/hyeonjin/별자리_만들기.java

@@ -0,0 +1,94 @@
+import java.io.*;
+import java.util.*;
+
+public class Main {
+    static List<Distance> distance;
+    static int[] check;
+    static int N;
+    public static void main(String[] args) throws Exception{
+        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
+        BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(System.out));
+        StringTokenizer str;
+
+        N = Integer.valueOf(br.readLine());
+        List<Point> star = new ArrayList<>();
+        distance = new ArrayList<>();
+        check = new int[N];
+        for(int i = 0; i < N; i++){
+            str = new StringTokenizer(br.readLine());
+            star.add(new Point(Double.valueOf(str.nextToken()), Double.valueOf(str.nextToken()), i));
+            check[i] = i;
+        }
+
+        for(int i = 0; i < N; i++){
+            for(int j = i + 1; j < N; j++){
+                distance.add(new Distance(star.get(i), star.get(j)));
+            }
+        }
+
+        Collections.sort(distance);
+        kruskal();
+    }
+
+    private static void kruskal() {
+        List<Distance> result = new ArrayList<>();
+        for(int i = 0; i < distance.size(); i++){
+            Distance dist = distance.get(i);
+
+            if(find_root(dist.p1.index) == find_root(dist.p2.index)) continue;
+
+            union_root(dist);
+            result.add(dist);
+
+            if(result.size() == N - 1){
+                double sum = 0;
+                for(int j = 0; j < result.size(); j++){
+                    sum += result.get(j).distance;
+                }
+
+                System.out.println(sum);
+                return;
+            }
+        }
+    }
+
+    public static void union_root(Distance dist){
+        int x = find_root(dist.p1.index);
+        int y = find_root(dist.p2.index);
+
+        if(x != y) check[y] = x;
+    }
+
+    public static int find_root(int x){
+        if(check[x] == x) return x;
+        return check[x] = find_root(check[x]);
+    }
+
+
+    public static class Point{
+        double x;
+        double y;
+        int index;
+        public Point(double x, double y, int index){
+            this.x = x;
+            this.y = y;
+            this.index = index;
+        }
+    }
+
+    public static class Distance implements Comparable<Distance>{
+        Point p1;
+        Point p2;
+        double distance;
+        public Distance(Point p1, Point p2){
+            this.p1 = p1;
+            this.p2 = p2;
+            this.distance = Math.round(Math.sqrt(Math.pow(p1.x - p2.x, 2) + Math.pow(p1.y - p2.y, 2)) * 100) / 100.0;
+        }
+
+        @Override
+        public int compareTo(Distance o){
+            return Double.compare(this.distance, o.distance);
+        }
+    }
+}