From 50e06d1f104f0096028785df681558693a8eb5df Mon Sep 17 00:00:00 2001
From: gson Liang <yuanyu90221@gmail.com>
Date: Tue, 6 Oct 2026 01:06:11 +0800
Subject: [PATCH] =?UTF-8?q?=E2=9C=A8=20(connected-undirect-node):=20golang?=
 =?UTF-8?q?=20with=20adjacency=20map=20with=20dfs?=
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---
 .../solution.go                               | 34 +++++++++++++++++--
 1 file changed, 32 insertions(+), 2 deletions(-)

diff --git a/go/graphs/0010-number-of-connected-components-in-an-undirected-graph/solution.go b/go/graphs/0010-number-of-connected-components-in-an-undirected-graph/solution.go
index d5b900b..92386b7 100644
--- a/go/graphs/0010-number-of-connected-components-in-an-undirected-graph/solution.go
+++ b/go/graphs/0010-number-of-connected-components-in-an-undirected-graph/solution.go
@@ -1,6 +1,36 @@
 package main
 
 func Solve(n int, edges [][]int) int {
-	// TODO(scaffold): implement, then delete this line
-	panic("not implemented")
+	// 1 建立 adjacency list 來紀錄每個節點相連的狀況
+	// 2 透過 DFS 逐個節點透過 adjacency list 來走訪節點，只要每次走完就把 counter 加一
+	adjacencyMap := make(map[int][]int, n)
+	for _, edge := range edges {
+		adjacencyMap[edge[0]] = append(adjacencyMap[edge[0]], edge[1])
+		adjacencyMap[edge[1]] = append(adjacencyMap[edge[1]], edge[0])
+	}
+	// 紀錄走訪過得
+	visited := make(map[int]struct{}, n)
+
+	var dfs func(node int)
+	dfs = func(node int) {
+		if _, ok := visited[node]; ok {
+			return
+		}
+		visited[node] = struct{}{}
+		adjacencyNodes := adjacencyMap[node]
+		for _, adjacencyNode := range adjacencyNodes {
+			if _, ok := visited[adjacencyNode]; !ok {
+				dfs(adjacencyNode)
+			}
+		}
+	}
+
+	result := 0
+	for i := 0; i < n; i++ {
+		if _, ok := visited[i]; !ok {
+			dfs(i)
+			result++
+		}
+	}
+	return result
 }