算法-直接插入排序

一、总体思想：将一个记录直接插入到一个已经排序好的列表中的对应位置，形成一个新的列表。直接插入排序为稳定排序。

二、排序过程(升序)：

1、认为第一个记录为有序列表。

2、从第二个记录开始，依次和已经排序的列表中记录做比较，如果被比较记录大于该记录， 则将被比较记录后移一位，否则将该记录插入到不大于它的记录之后。

3、依次处理后续记录。

三、算法效率

时间复杂度：O(n^2)

空间复杂度：O(1)

四、代码-数组实现方式

/********************************************
Author: zchshen
Date: 2017-07-09
Brief: ascending order of insert sort by array.
********************************************/

#include <iostream>
#include <stdlib.h>
#include <string.h>

const int MaxArraySize = 128;

void InsertSortUp(int *array, const int &count){
int tmp = 0;

for (int i=1; i<count; i++){
tmp = array[i];
for (int j=i-1; j>=0; j--){
if (array[i] < array[j]){
array[j+1] = array[j];
}
else{
array[j+1] = tmp;
break;
}
}
}
}

int main(int argc, char **argv){
if (argc < 2){
std::cout << argv[0] << " your_array" << std::endl;
std::cout << "Example: " << argv[0] << " 1 3 2 4" << std::endl;
exit(1);
}

if (argc > MaxArraySize){
std::cout << "Input Array too long!" << std::endl;
}

std::cout << argc << std::endl;
std::cout << argv[1] << std::endl << std::endl;

int ArraySize = argc - 1;
int *Array = new int[MaxArraySize + 1];
memset(Array, 0, MaxArraySize + 1);

std::cout << "Org order:" << std::endl;
for (int i=1; i<argc; i++){
Array[i-1] = atoi(argv[i]);
std::cout << Array[i-1] << " ";
}
std::cout << std::endl;

InsertSortUp(Array, ArraySize);

std::cout << "ascending order:" << std::endl;
for (int i=0; i<ArraySize; i++){
std::cout << Array[i] << " ";
}
std::cout << std::endl;

return 0;
}

六、代码-链表实现方式

/*************************************
Author: zchshen
Date: 2017-07-25
Brief: ascending order of insert sort by link list(include head)
**************************************/

#include <iostream>
#include <stdlib.h>
#include <stdint.h>
#include <assert.h>

using namespace std;

typedef struct Node{
int data;
struct Node* next;
}LinkNode;

void CreatListByEndInsert(LinkNode* head){
assert(head);
head->next = NULL;

LinkNode* Index = head;
LinkNode* node;
srand((uint32_t)time(NULL));
for (int i=0; i<20; i++){
try{
node = new LinkNode();
}
catch(...){
return;
}

node->data = rand()%100;
Index->next = node;
Index = node;
}
node->next = NULL;
}

void DisPlayList(LinkNode* head){
assert(head);

LinkNode* Index = head->next;
while (NULL != Index){
cout << "Data: " << Index->data << endl;
Index = Index->next;
}
cout << endl;
}

void ReleaseList(LinkNode* head){
assert(head);

LinkNode* Index = head->next;
while (NULL != Index){
delete Index;
Index = NULL;
}
delete head;
head = NULL;
}

void InsertSortUp(LinkNode* head){
assert(head);
assert(head->next);

LinkNode* curNode = head->next;
LinkNode* frontNode = head;
LinkNode* remainNode = curNode->next;
LinkNode* insertNode = remainNode;
curNode->next = NULL;

while (remainNode){
while (NULL != curNode && insertNode->data >= curNode->data){
frontNode = curNode;
curNode = curNode->next;
}

remainNode = remainNode->next;
frontNode->next = insertNode;
insertNode->next = curNode;
insertNode = remainNode;
curNode = head;
frontNode = head;
}
}

int main(int argc, char** argv){

LinkNode* head = NULL;
try{
head = new LinkNode();
}
catch(...){
exit(1);
}

CreatListByEndInsert(head);
DisPlayList(head);
InsertSortUp(head);
DisPlayList(head);
ReleaseList(head);

return 0;
}