1 /*插入排序(insert Sort) O(n^2)*/
2 public List<int> InsertSort(int[] arr)
3 {
4 List<int> tempArr = new List<int>();
5 tempArr.Add(arr[0]);
6 bool flag = false;
7 for (int i = 1; i < arr.Length; i++)
8 {
9 for (int j = 0; j < tempArr.Count; j++)
10 {
11 if (arr[i] < tempArr[j])
12 {
13 tempArr.Insert(j, arr[i]);
14 flag = true;
15 break;
16 }
17 }
18 if (!flag)
19 {
20 tempArr.Add(arr[i]);
21 }
22 flag = false;
23 }
24 return tempArr;
25 }
1 /*归并排序(merge Sort) O(nlog2(n)) 非递归*/
2 public List<int> MergeSort(int[] arr)
3 {
4 List<int> tempArr = new List<int>();//保存最后得到的数组
5 int twoDouble = 2;//保存2的幂次方
6 List<int> preArr = new List<int>();//保存前一个数组
7 for(int i=0;i<arr.Length;i++){
8 preArr.Add(arr[i]);
9 }
10 while (arr.Length > twoDouble/2)//当数组的长度小于2的幂次方的长度时，终止
11 {
12 List<int> subArr = new List<int>();//拿到合并后的数组
13 tempArr.Clear();
14 if (arr.Length / twoDouble > 0)//不是最后一组
15 {
16 for (int i = 0; i < arr.Length / twoDouble; i++)
17 {//一定可以有2个或以上的组,而且是可以平分的
18 List<int> leftArr = new List<int>();
19 List<int> rightArr = new List<int>();
20 for (int j = i * twoDouble; j < (i * twoDouble + twoDouble / 2); j++)
21 {
22 leftArr.Add(preArr[j]);
23 }
24 for (int j = (i * twoDouble + twoDouble / 2); j < (i * twoDouble + twoDouble); j++)
25 {
26 rightArr.Add(preArr[j]);
27 }
28 subArr = MergeSortSubProgram(leftArr, rightArr);
29 for (int j = 0; j < subArr.Count; j++) //将拿到的合并后的数组添加到preArr
30 {
31 tempArr.Add(subArr[j]);
32 }
33 subArr.Clear();
34 }
35 if ((arr.Length - (arr.Length / twoDouble) * twoDouble) <= twoDouble / 2)//如果最后的数不能分为2组
36 {
37 for (int i = (arr.Length / twoDouble) * twoDouble; i < arr.Length; i++)
38 {
39 tempArr.Add(preArr[i]);
40 }
41 }
42 else {
43 List<int> leftArr = new List<int>();
44 List<int> rightArr = new List<int>();
45 for (int i = (arr.Length / twoDouble) * twoDouble; i < (arr.Length / twoDouble) * twoDouble+twoDouble / 2; i++)
46 {
47 leftArr.Add(preArr[i]);
48 }
49 for (int i = (arr.Length / twoDouble) * twoDouble + twoDouble / 2; i < arr.Length; i++)
50 {
51 rightArr.Add(preArr[i]);
52 }
53 subArr = MergeSortSubProgram(leftArr, rightArr);//最后一组合并
54 for (int i = 0; i < subArr.Count; i++)
55 {
56 tempArr.Add(subArr[i]);
57 }
58 subArr.Clear();
59 }
60 }
61 else if (arr.Length / twoDouble == 0) //最后一组
62 {
63 List<int> leftArr = new List<int>();
64 List<int> rightArr = new List<int>();
65 for (int i = 0; i < twoDouble / 2; i++) {
66 leftArr.Add(preArr[i]);
67 }
68 for (int i = twoDouble / 2; i < arr.Length; i++) {
69 rightArr.Add(preArr[i]);
70 }
71 subArr = MergeSortSubProgram(leftArr, rightArr);//最后一组合并
72 for (int i = 0; i < subArr.Count; i++) {
73 tempArr.Add(subArr[i]);
74 }
75 subArr.Clear();
76 }
77
78 //preArr = tempArr;//使preArr指向tempArr了
79 twoDouble *= 2;
80 preArr.Clear();
81 for (int x = 0; x < tempArr.Count; x++) {
82 Console.Write(tempArr[x] + " ");
83 preArr.Add(tempArr[x]);
84 }
85 Console.WriteLine();
86 }
87 return tempArr;
88 }
89 //实现左右2边数组从小到大合并
90 List<int> MergeSortSubProgram(List<int> leftArr,List<int> rightArr)
91 {
92 List<int> tempArr = new List<int>();
93 bool flag = true;
94 int leftPos = 0, rightPos = 0;
95
96 while (flag) {
97 if (leftArr[leftPos] < rightArr[rightPos]) //当左边的数比右边小
98 {
99 tempArr.Add(leftArr[leftPos]);
100 leftPos++;
101 }
102 else {
103 tempArr.Add(rightArr[rightPos]);
104 rightPos++;
105 }
106 //当其中一组到底之后
107 if (leftPos == leftArr.Count || rightPos == rightArr.Count) {
108 flag = false;
109 if (leftPos == leftArr.Count) {
110 for (int i = rightPos; i < rightArr.Count; i++) {
111 tempArr.Add(rightArr[i]);
112 }
113 }
114 else if (rightPos == rightArr.Count) {
115 for (int i = leftPos; i < leftArr.Count; i++) {
116 tempArr.Add(leftArr[i]);
117 }
118 }
119 }
120 }
121
122 return tempArr;
123 }
