✨86.分隔链表

Author: techoc

README.md

@@ -150,6 +150,7 @@
 - [7.整数反转](leetcode/medium/7.go)
 - [36.有效的数独](leetcode/medium/36.go)
 - [73.矩阵置零](leetcode/medium/73.go)
+- [86.分隔链表](leetcode/medium/t86/solution.go)
 - [93.复原 IP 地址](leetcode/medium/93.go)
 - [99.恢复二叉搜索树](leetcode/medium/99.go)
 - [105.从前序与中序遍历序列构造二叉树](leetcode/medium/105.go)

leetcode/medium/t86/solution.go

@@ -0,0 +1,47 @@
+package t86
+
+/**
+ * Definition for singly-linked list.
+ * type ListNode struct {
+ *     Val int
+ *     Next *ListNode
+ * }
+ */
+
+// 86. 分隔链表
+// https://leetcode.cn/problems/partition-list
+func partition(head *ListNode, x int) *ListNode {
+	// 创建两个链表，分别存储小于x和等于x的节点
+	less := &ListNode{}
+	more := &ListNode{}
+	// 创建两个链表的虚拟头节点 方便插入节点
+	lessHead := less
+	moreHead := more
+	// 遍历链表，将节点插入对应的链表
+	for head != nil {
+		if head.Val < x {
+			// 小于 x 的值放入 less 链表
+			less.Next = head
+			less = less.Next
+			head = head.Next
+			// 断开 head 和 less 的连接
+			less.Next = nil
+		} else {
+			// 大于等于 x 的值放入 more 链表
+			more.Next = head
+			more = more.Next
+			head = head.Next
+			// 断开 head 和 more 的连接
+			more.Next = nil
+		}
+	}
+	// 使用初始化的虚拟头节点 将 more 链表连接在 less 链表之后
+	less.Next = moreHead.Next
+	// 返回 less 链表虚拟头节点的下一个节点
+	return lessHead.Next
+}
+
+type ListNode struct {
+	Val  int
+	Next *ListNode
+}

leetcode/medium/t86/solution_test.go

@@ -0,0 +1,81 @@
+package t86
+
+import (
+	"reflect"
+	"testing"
+)
+
+func TestPartition(t *testing.T) {
+	tests := []struct {
+		name string
+		head *ListNode
+		x    int
+		want *ListNode
+	}{
+		{
+			name: "Case 1",
+			head: &ListNode{
+				Val: 1,
+				Next: &ListNode{
+					Val: 4,
+					Next: &ListNode{
+						Val: 3,
+						Next: &ListNode{
+							Val: 2,
+							Next: &ListNode{
+								Val: 5,
+								Next: &ListNode{
+									Val: 2,
+								},
+							},
+						},
+					},
+				},
+			},
+			x: 3,
+			want: &ListNode{
+				Val: 1,
+				Next: &ListNode{
+					Val: 2,
+					Next: &ListNode{
+						Val: 2,
+						Next: &ListNode{
+							Val: 4,
+							Next: &ListNode{
+								Val: 3,
+								Next: &ListNode{
+									Val: 5,
+								},
+							},
+						},
+					},
+				},
+			},
+		},
+		{
+			name: "Case 2",
+			head: &ListNode{
+				Val: 2,
+				Next: &ListNode{
+					Val: 1,
+				},
+			},
+			x: 2,
+			want: &ListNode{
+				Val: 1,
+				Next: &ListNode{
+					Val: 2,
+				},
+			},
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			if got := partition(tt.head, tt.x); !reflect.DeepEqual(got, tt.want) {
+				//if got := partition(tt.head, tt.x); !equals(got, tt.want) {
+				t.Errorf("partition() = %v, want %v", got, tt.want)
+			}
+		})
+	}
+}