Merge pull request #2459 from lynndove/master

1971. 寻找图中是否存在路径 添加go解法

problems/1971.寻找图中是否存在路径.md

@@ -284,6 +284,48 @@ var validPath = function(n, edges, source, destination) {
 };
 ```
 
+### Go
+
+```go
+func validPath(n int, edges [][]int, source int, destination int) bool {
+	n = 200005
+	father := make([]int, n)
+	// 并查集初始化
+	for i := 0; i < n; i++ {
+		father[i] = i
+	}
+
+	var find func(u int) int // 并查集里寻根的过程
+	find = func(u int) int {
+		// 如果根就是自己，直接返回
+		// 如果根不是自己，就根据数组下标一层一层向下找
+		if u == father[u] {
+			return u
+		}
+		return find(father[u])
+	}
+
+	var join func(u, v int) // 将 v->u 这条边加入并查集
+	join = func(u, v int) {
+		u = find(u)
+		v = find(v)
+		if u == v {
+			return
+		}
+		father[v] = u
+	}
+
+	for i := 0; i < len(edges); i++ {
+		join(edges[i][0], edges[i][1])
+	}
+
+	source = find(source)
+	destination = find(destination)
+	return source == destination
+}
+
+```
+
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