Merge pull request #266 from betNevS/master

更新 0019.删除链表的倒数第N个节点 go版本

problems/0019.删除链表的倒数第N个节点.md

@@ -114,24 +114,28 @@ class Solution {
 ```
 Go:
 ```Go
+/**
+ * Definition for singly-linked list.
+ * type ListNode struct {
+ *     Val int
+ *     Next *ListNode
+ * }
+ */
 func removeNthFromEnd(head *ListNode, n int) *ListNode {
-    result:=&ListNode{}
-    result.Next=head
-    var pre *ListNode
-    cur:=result
-
-    i:=1
-    for head!=nil{
-        if i>=n{
-            pre=cur
-            cur=cur.Next
+    dummyHead := &ListNode{}
+    dummyHead.Next = head
+    cur := head
+    prev := dummyHead
+    i := 1
+    for cur != nil {
+        cur = cur.Next
+        if i > n {
+            prev = prev.Next
         }
-        head=head.Next
         i++
     }
-    pre.Next=pre.Next.Next
-    return result.Next
-
+    prev.Next = prev.Next.Next
+    return dummyHead.Next
 }
 ```
 

problems/0024.两两交换链表中的节点.md

@@ -153,6 +153,19 @@ func swapPairs(head *ListNode) *ListNode {
 }
 ```
 
+```go
+// 递归版本
+func swapPairs(head *ListNode) *ListNode {
+    if head == nil || head.Next == nil {
+        return head
+    }
+    next := head.Next
+    head.Next = swapPairs(next.Next)
+    next.Next = head
+    return next
+}
+```
+
 Javascript:
 ```javascript
 var swapPairs = function (head) {