add new solutions

solutions/1/q114/solution.go

@@ -0,0 +1,35 @@
+package q114
+
+type TreeNode struct {
+	Val   int
+	Left  *TreeNode
+	Right *TreeNode
+}
+
+func fl(node *TreeNode) (head, tail *TreeNode) {
+	if node == nil {
+		return nil, nil
+	}
+	head, tail = node, node
+
+	lhead, ltail := fl(node.Left)
+	rhead, rtail := fl(node.Right)
+
+	if lhead != nil {
+		node.Left = nil
+		node.Right = lhead
+		tail = ltail
+	}
+
+	if rhead != nil {
+		tail.Right = rhead
+		tail = rtail
+	}
+	return
+}
+
+func flatten(root *TreeNode) {
+	fl(root)
+}
+
+var _ = flatten