u

2026-06-21 13:11:31 +10:00
parent 3bce899398
commit 35c362681e
6 changed files with 533 additions and 0 deletions
@@ -0,0 +1,83 @@
+package top100liked
+
+import (
+	"fmt"
+	"testing"
+)
+
+// https://leetcode.cn/problems/remove-nth-node-from-end-of-list/description/?envType=study-plan-v2&envId=top-100-liked
+
+type ListNode struct {
+	Val  int
+	Next *ListNode
+}
+
+// func removeNthFromEnd(head *ListNode, n int) *ListNode {
+// 	pre := &ListNode{Next: head}
+// 	p := head
+// 	l := 0
+// 	for p != nil {
+// 		l++
+// 		p = p.Next
+// 	}
+// 	p1 := pre
+// 	p2 := pre.Next.Next
+// 	for range l - n {
+// 		p1 = p1.Next
+// 		p2 = p2.Next
+// 	}
+// 	p1.Next = p2
+// 	return pre.Next
+// }
+
+// 双指针
+func removeNthFromEnd(head *ListNode, n int) *ListNode {
+	dummy := &ListNode{0, head}
+	first, second := head, dummy
+	for range n {
+		first = first.Next
+	}
+	for first != nil {
+		first = first.Next
+		second = second.Next
+	}
+	second.Next = second.Next.Next
+	return dummy.Next
+}
+
+func Test(t *testing.T) {
+	input1 := &ListNode{
+		Val: 1,
+		Next: &ListNode{
+			Val: 2,
+			Next: &ListNode{
+				Val: 3,
+				Next: &ListNode{
+					Val: 4,
+					Next: &ListNode{
+						Val:  5,
+						Next: nil,
+					},
+				},
+			},
+		},
+	}
+	input2 := &ListNode{
+		Val: 1,
+		Next: &ListNode{
+			Val:  2,
+			Next: nil,
+		},
+	}
+	output := removeNthFromEnd(input1, 2)
+	for output != nil {
+		fmt.Print(output.Val, " ")
+		output = output.Next
+	}
+	fmt.Println()
+	output = removeNthFromEnd(input2, 1)
+	for output != nil {
+		fmt.Print(output.Val, " ")
+		output = output.Next
+	}
+}