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top-100-liked/21/21_test.go

@@ -1,5 +1,7 @@
 package top100liked
 
+// https://leetcode.cn/problems/search-a-2d-matrix-ii/?envType=study-plan-v2&envId=top-100-liked
+
 import (
 	"fmt"
 	"testing"

top-100-liked/22/22_test.go

@@ -0,0 +1,21 @@
+package top100liked
+
+// https://leetcode.cn/problems/intersection-of-two-linked-lists/?envType=study-plan-v2&envId=top-100-liked
+
+type ListNode struct {
+	Val  int
+	Next *ListNode
+}
+
+func getIntersectionNode(headA, headB *ListNode) *ListNode {
+	vis := map[*ListNode]bool{}
+	for tmp := headA; tmp != nil; tmp = tmp.Next {
+		vis[tmp] = true
+	}
+	for tmp := headB; tmp != nil; tmp = tmp.Next {
+		if vis[tmp] {
+			return tmp
+		}
+	}
+	return nil
+}

top-100-liked/23/23_test.go

@@ -0,0 +1,55 @@
+package top100liked
+
+import (
+	"fmt"
+	"testing"
+)
+
+// https://leetcode.cn/problems/reverse-linked-list/description/?envType=study-plan-v2&envId=top-100-liked
+
+type ListNode struct {
+	Val  int
+	Next *ListNode
+}
+
+func reverseList(head *ListNode) *ListNode {
+	if head == nil {
+		return nil
+	}
+	var last *ListNode = nil
+	h := head
+	for h.Next != nil {
+		tmp := h.Next
+		h.Next = last
+		last = h
+		h = tmp
+	}
+	h.Next = last
+	return h
+}
+
+func TestS23(t *testing.T) {
+	input := ListNode{
+		Val: 1,
+		Next: &ListNode{
+			Val: 2,
+			Next: &ListNode{
+				Val: 3,
+				Next: &ListNode{
+					Val: 4,
+					Next: &ListNode{
+						Val:  5,
+						Next: nil,
+					},
+				},
+			},
+		},
+	}
+	output := reverseList(&input)
+
+	for output.Next != nil {
+		fmt.Println(output.Val)
+		output = output.Next
+	}
+	fmt.Println(output.Val)
+}

top-100-liked/24/24_test.go

@@ -0,0 +1,44 @@
+package top100liked
+
+import (
+	"fmt"
+	"testing"
+)
+
+// https://leetcode.cn/problems/palindrome-linked-list/description/?envType=study-plan-v2&envId=top-100-liked
+
+type ListNode struct {
+	Val  int
+	Next *ListNode
+}
+
+func isPalindrome(head *ListNode) bool {
+	vals := []int{}
+	for ; head != nil; head = head.Next {
+		vals = append(vals, head.Val)
+	}
+	n := len(vals)
+	for i, v := range vals[:n/2] {
+		if v != vals[n-1-i] {
+			return false
+		}
+	}
+	return true
+}
+
+func TestS24(t *testing.T) {
+	input := ListNode{
+		Val: 1,
+		Next: &ListNode{
+			Val: 2,
+			Next: &ListNode{
+				Val: 2,
+				Next: &ListNode{
+					Val:  1,
+					Next: nil,
+				},
+			},
+		},
+	}
+	fmt.Println(isPalindrome(&input))
+}

top-100-liked/25/25_test.go

@@ -0,0 +1,58 @@
+package top100liked
+
+import (
+	"fmt"
+	"testing"
+)
+
+// https://leetcode.cn/problems/linked-list-cycle/description/?envType=study-plan-v2&envId=top-100-liked
+
+type ListNode struct {
+	Val  int
+	Next *ListNode
+}
+
+// func hasCycle(head *ListNode) bool {
+// 	_map := make(map[*ListNode]bool)
+// 	for head != nil {
+// 		if _map[head] {
+// 			return true
+// 		}
+// 		_map[head] = true
+// 		head = head.Next
+// 	}
+// 	return false
+// }
+
+func hasCycle(head *ListNode) bool {
+	if head == nil || head.Next == nil {
+		return false
+	}
+	slow, fast := head, head.Next
+	for fast != slow {
+		if fast == nil || fast.Next == nil {
+			return false
+		}
+		slow = slow.Next
+		fast = fast.Next.Next
+	}
+	return true
+}
+
+func TestS24(t *testing.T) {
+	input := &ListNode{
+		Val: 3,
+		Next: &ListNode{
+			Val: 2,
+			Next: &ListNode{
+				Val: 0,
+				Next: &ListNode{
+					Val:  -4,
+					Next: nil,
+				},
+			},
+		},
+	}
+	input.Next.Next.Next.Next = input.Next
+	fmt.Println(hasCycle(input))
+}