[UnionFind] programmers-네트워크

Author: Seogeurim

README.md

@@ -246,6 +246,7 @@
 | 02  |     | [Baekjoon-2252 줄 세우기](./src/Graph/P2252)   | [위상정렬](./notes/Graph/TopologicalSort.md) |
 | 03  |     | [Baekjoon-4386 별자리 만들기](./src/Graph/P4386)| MST - Kruskal |
 | 04  |     | [Baekjoon-16562 친구비](./src/Graph/P16562)    | MST - Kruskal |
+| 05  |     | [Programmers 네트워크](./src/Graph/prg43162)   |      |
 
 ## Math
 

src/Graph/prg43162/Main.java

@@ -0,0 +1,50 @@
+package Graph.prg43162;
+
+import java.util.HashSet;
+
+public class Main {
+
+    public static void main(String[] args) {
+        Solution sol = new Solution();
+        System.out.println(sol.solution(3, new int[][]{{1, 1, 0}, {1, 1, 0}, {0, 0, 1}}));
+        System.out.println(sol.solution(3, new int[][]{{1, 1, 0}, {1, 1, 1}, {0, 1, 1}}));
+    }
+}
+
+// 1 1 0
+// 1 1 0
+// 0 0 1
+
+// 1 1 0
+// 1 1 1
+// 0 1 1
+
+class Solution {
+
+    static int[] root;
+
+    public int solution(int n, int[][] computers) {
+        root = new int[n];
+        for (int i = 0; i < n; i++) root[i] = i;
+
+        for (int i = 0; i < n; i++) {
+            for (int j = i+1; j < n; j++) {
+                if (computers[i][j] == 1) merge(i, j);
+            }
+        }
+
+        HashSet<Integer> set = new HashSet<>();
+        for (int i = 0; i < n; i++) set.add(find(i));
+
+        return set.size();
+    }
+
+    static int find(int n) {
+        if (root[n] == n) return n;
+        return root[n] = find(root[n]);
+    }
+
+    static void merge(int a, int b) {
+        root[find(b)] = find(a);
+    }
+}

src/Graph/prg43162/README.md

@@ -0,0 +1,3 @@
+## [programmers - 깊이/너비 우선 탐색(DFS/BFS)] 네트워크
+
+![image](https://user-images.githubusercontent.com/22045163/109410733-617ab900-79e0-11eb-971c-eedfc9d6f6f9.png)