add new solutions

solutions/1/q138/solution.go

@@ -0,0 +1,34 @@
+package q138
+
+type Node struct {
+	Val    int
+	Next   *Node
+	Random *Node
+}
+
+func copyRandomList(head *Node) *Node {
+	idx := make(map[*Node]*Node, 256)
+
+	p := head
+	for p != nil {
+		newNode := *p // copy
+		idx[p] = &newNode
+		p = p.Next
+	}
+
+	p = head
+	for p != nil {
+		newNode := idx[p]
+		if newNode.Next != nil {
+			newNode.Next = idx[newNode.Next]
+		}
+		if newNode.Random != nil {
+			newNode.Random = idx[newNode.Random]
+		}
+		p = p.Next
+	}
+
+	return idx[head]
+}
+
+var _ = copyRandomList