u

2026-06-21 16:31:54 +10:00
parent 35c362681e
commit c4cfce490e
3 changed files with 348 additions and 0 deletions
@@ -0,0 +1,146 @@
+package top100liked
+
+import (
+	"fmt"
+	"testing"
+)
+
+// https://leetcode.cn/problems/reverse-nodes-in-k-group/description/?envType=study-plan-v2&envId=top-100-liked
+
+type ListNode struct {
+	Val  int
+	Next *ListNode
+}
+
+// 暴力解，非常慢，但是能通过
+// func mergeKLists(lists []*ListNode) *ListNode {
+// 	if lists == nil {
+// 		return nil
+// 	}
+// 	dummy := &ListNode{}
+// 	p := dummy
+// 	var minValue int
+// 	minIndex := -1
+// 	for {
+// 		for i := range lists {
+// 			if lists[i] != nil {
+// 				if minIndex == -1 {
+// 					minValue = lists[i].Val
+// 					minIndex = i
+// 				}
+// 				if lists[i].Val < minValue {
+// 					minValue = lists[i].Val
+// 					minIndex = i
+// 				}
+// 			}
+// 		}
+// 		if minIndex == -1 {
+// 			return nil
+// 		}
+// 		p.Next = lists[minIndex]
+// 		p = p.Next
+// 		lists[minIndex] = lists[minIndex].Next
+// 		minIndex = -1
+// 		allNil := true
+// 		for i := range lists {
+// 			if lists[i] != nil {
+// 				allNil = false
+// 				break
+// 			}
+// 		}
+// 		if allNil {
+// 			break
+// 		}
+// 	}
+// 	return dummy.Next
+// }
+
+func mergeTwoLists(list1 *ListNode, list2 *ListNode) *ListNode {
+	p1, p2 := list1, list2
+	p := &ListNode{}
+	res := p
+	for p1 != nil && p2 != nil {
+		if p1.Val <= p2.Val {
+			p.Next = p1
+			p = p.Next
+			p1 = p1.Next
+		} else {
+			p.Next = p2
+			p = p.Next
+			p2 = p2.Next
+		}
+	}
+	for p1 != nil {
+		p.Next = p1
+		p = p.Next
+		p1 = p1.Next
+	}
+	for p2 != nil {
+		p.Next = p2
+		p = p.Next
+		p2 = p2.Next
+	}
+	return res.Next
+}
+
+// 分治归并
+func mergeKLists(lists []*ListNode) *ListNode {
+	if len(lists) == 0 || lists == nil {
+		return nil
+	}
+	if len(lists) == 1 {
+		return lists[0]
+	}
+	l := []*ListNode{}
+	for i := range len(lists) / 2 {
+		l = append(l, mergeTwoLists(lists[2*i], lists[2*i+1]))
+	}
+	if len(lists)%2 != 0 {
+		l = append(l, lists[len(lists)-1])
+	}
+	return mergeKLists(l)
+}
+
+func Test1(t *testing.T) {
+	input := []*ListNode{
+		{
+			Val: 1,
+			Next: &ListNode{
+				Val: 4,
+				Next: &ListNode{
+					Val:  5,
+					Next: nil,
+				},
+			},
+		},
+		{
+			Val: 1,
+			Next: &ListNode{
+				Val: 3,
+				Next: &ListNode{
+					Val:  4,
+					Next: nil,
+				},
+			},
+		},
+		{
+			Val: 2,
+			Next: &ListNode{
+				Val:  6,
+				Next: nil,
+			},
+		},
+	}
+	output := mergeKLists(input)
+	for output != nil {
+		fmt.Print(output.Val, " ")
+		output = output.Next
+	}
+}
+
+func Test2(t *testing.T) {
+	mergeKLists(nil)
+}
+func Test3(t *testing.T) {
+	mergeKLists([]*ListNode{nil})
+}