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src/main/java/com/dota/graph/_2685/Solution.java

@@ -0,0 +1,47 @@
+package com.dota.graph._2685;
+
+import java.util.*;
+
+class Solution {
+	public static void main(String[] args) {
+		new Solution().countCompleteComponents(6, new int[][]{{0,1},{0,2},{1,2},{3,4}});
+	}
+	public int countCompleteComponents(int n, int[][] edges) {
+		List<Integer>[] g = new ArrayList[n];
+		Arrays.setAll(g, i -> {
+			var list = new ArrayList<>();
+			list.add(i);
+			return list;
+		});
+
+		var book = new boolean[n];
+		for (int[] edge : edges) {
+			g[edge[0]].add(edge[1]);
+			g[edge[1]].add(edge[0]);
+		}
+
+		var sum = 0;
+		for (int i = 0; i < n; i++) {
+			if (!book[i]) {
+				var size = dfs(book, i, g);
+				int temp = 0;
+				for (Integer integer : g[i]) {
+					temp += g[integer].size();
+				}
+				if (size * g[i].size() == temp) {
+					sum++;
+				}
+			}
+		}
+		return sum;
+	}
+
+	int dfs(boolean[] book, int i, List<Integer>[] g) {
+		var set = 1;
+		book[i] = true;
+		for (Integer j : g[i]) {
+			if (!book[j]) set += dfs(book, j, g);
+		}
+		return set;
+	}
+}