add leetcode 147

Author: saenaii

src/0147.Insertion-Sort-List/ListNode.go

@@ -0,0 +1,61 @@
+package Solution
+
+import (
+	"fmt"
+	"math/rand"
+)
+
+type ListNode struct {
+	Val  int
+	Next *ListNode
+}
+
+//	比较结果
+func isEqual(l1 *ListNode, l2 *ListNode) bool {
+
+	for l1 != nil && l2 != nil {
+		if l1.Val != l2.Val {
+			return false
+		}
+		l1 = l1.Next
+		l2 = l2.Next
+	}
+	if l1 == nil && l2 != nil {
+		return false
+	}
+	if l1 != nil && l2 == nil {
+		return false
+	}
+	return true
+}
+
+func PrintList(head *ListNode) {
+	for head != nil {
+		fmt.Print(head.Val, "->")
+		head = head.Next
+	}
+	fmt.Println()
+}
+
+// 根据数组反序列化链表
+func UnmarshalListBySlice(nums []int) *ListNode {
+	head := &ListNode{Val: -1, Next: nil}
+	tmp := head
+	for _, v := range nums {
+		tmp.Next = &ListNode{Val: v, Next: nil}
+		tmp = tmp.Next
+	}
+	return head.Next
+}
+
+// 随机初始化链表
+func UnmarshalListByRand(max_num int, len int) *ListNode {
+	head := &ListNode{Val: -1, Next: nil}
+	tmp := head
+
+	for i := 0; i < len; i++ {
+		tmp.Next = &ListNode{Val: rand.Intn(max_num), Next: nil}
+		tmp = tmp.Next
+	}
+	return head.Next
+}

src/0147.Insertion-Sort-List/README.md

@@ -0,0 +1,65 @@
+# [147. Insertion Sort List][title]
+
+## Description
+Sort a linked list using insertion sort.
+
+### Algorithm of Insertion Sort:
+1. Insertion sort iterates, consuming one input element each repetition, and growing a sorted output list.
+1. At each iteration, insertion sort removes one element from the input data, finds the location it belongs within the sorted list, and inserts it there.
+1. It repeats until no input elements remain.
+
+**Example 1:**
+```
+Input: 4->2->1->3
+Output: 1->2->3->4
+```
+
+**Example 2:**
+```
+Input: -1->5->3->4->0
+Output: -1->0->3->4->5
+```
+
+**Tags:** Linked List
+
+## 题意
+> 对一个单链表进行插入排序。
+
+## 题解
+
+### 思路 1
+> 构造一个新的链表，每次将原链表中一个节点插入到新链表中合适的位置
+
+```go
+func insertionSortList(head *ListNode) *ListNode {
+    if nil == head {
+        return nil
+    }
+    newHead := new(ListNode)
+    newHead.Next = &ListNode{head.Val, nil}
+    
+    head = head.Next
+    for head != nil {
+        prev, current := newHead, newHead.Next
+        for current != nil {
+            if head.Val < current.Val {
+                prev.Next = &ListNode{head.Val, current}
+                break
+            }
+            prev, current = prev.Next, current.Next
+        }
+        if nil == current && head.Val >= prev.Val {
+            prev.Next = &ListNode{head.Val, nil}
+        }
+        head = head.Next
+    }
+    return newHead.Next
+}
+```
+
+## 结语
+
+如果你同我一样热爱数据结构、算法、LeetCode，可以关注我 GitHub 上的 LeetCode 题解：[awesome-golang-leetcode][me]
+
+[title]: https://leetcode.com/problems/insertion-sort-list/
+[me]: https://github.com/kylesliu/awesome-golang-leetcode

src/0147.Insertion-Sort-List/Solution.go

@@ -0,0 +1,26 @@
+package Solution
+
+func Solution(head *ListNode) *ListNode {
+	if nil == head {
+		return nil
+	}
+	newHead := new(ListNode)
+	newHead.Next = &ListNode{head.Val, nil}
+
+	head = head.Next
+	for head != nil {
+		prev, current := newHead, newHead.Next
+		for current != nil {
+			if head.Val < current.Val {
+				prev.Next = &ListNode{head.Val, current}
+				break
+			}
+			prev, current = prev.Next, current.Next
+		}
+		if nil == current && head.Val >= prev.Val {
+			prev.Next = &ListNode{head.Val, nil}
+		}
+		head = head.Next
+	}
+	return newHead.Next
+}

src/0147.Insertion-Sort-List/Solution_test.go

@@ -0,0 +1,33 @@
+package Solution
+
+import "testing"
+
+func TestSolution(t *testing.T) {
+	TestCases := []struct{
+		name string
+		inputs []int
+		expect []int
+	}{
+		{
+			"TestCase 1",
+			[]int{4,2,1,3},
+			[]int{1,2,3,4},
+		},
+		{
+			"TestCase 2",
+			[]int{-1,5,3,4,0},
+			[]int{-1,0,3,4,5},
+		},
+	}
+
+	for _, c := range TestCases {
+		t.Run(c.name, func(t *testing.T) {
+			ret := Solution(UnmarshalListBySlice(c.inputs))
+			if !isEqual(ret, UnmarshalListBySlice(c.expect)) {
+				PrintList(ret)
+				PrintList(UnmarshalListBySlice(c.expect))
+				t.Fatalf("expected: %v, but got: %v, with inputs: %v", c.expect, ret, c.inputs)
+			}
+		})
+	}
+}