題目要求：
1、使用c語言實現，不能使用c++的stl容器，map、vector等等
2、自己定義數據結構
3、如果需要排序，自己寫排序算法
股票交易中，高峯期委託買賣數量是十分大的，尤其在9:30分左右，而證券公司關心的搶手的信息條數會遠小於委託買賣數量。實際情況是題目中的n會非常大，而s很小，因此需要考慮算法的時間複雜度。
題目如下：
京東筆試-交易清單（京東2016實習生真題）
題目描述
金融證券行業超好的薪酬待遇，吸引了大批的求職者前往應聘，小東也不例外，準備應聘一家證券公司。面試官爲考察她的數據分析、處理和編碼能力，爲她準備了以下問題。
股票交易中，委託是指股票交易者在證券公司買賣股票。每手委託包括一個委託單號i、價格pi、買入或賣出標記di及交易數量qi。
交易處理中，需要把同類業務（買入或賣出）中相同價格的所有委託合併起來，形成一個清單。清單的第一部分爲按價格降序排列的合併後的賣出委託，緊隨其後的是按相同順序排列的買入合併委託。證券公司比較關心的是比較搶手的s條合併委託信息，需要得到買入及賣出最搶手的s條合併委託。對於買入委託，搶手的是指報價高的委託，而賣出委託中報價低的較爲搶手。若買或賣的合併委託數小於s條，則全部列入清單中。
現在小東拿到的是n個委託，請你幫忙找出最搶手的s個合併委託。
輸入
輸入有若干組，每組的第一行爲兩個正整數n和s（1<=n<=1000，1<=s<=50），分別表示委託數和最搶手的清單數，接下來的n行爲具體的委託信息，每行包含3部分，第一部分爲一個字母‘B’或‘S’，表示買入或賣出，後兩部分爲兩個整數p和q，表示報價和數量。任何賣出委託的報價都比買入委託的報價高。
輸出
輸出不超過2s行合併委託清單，格式與輸入相同。
樣例輸入
6 2
B 10 3
S 50 2
S 40 1
S 50 6
B 20 4
B 25 10
樣例輸出
S 40 1
S 50 8
B 25 10
B 20 4
#include<stdio.h>
#include<stdlib.h>
#include<assert.h>
#include<stdbool.h>
typedef struct {
unsigned int in;
unsigned int out;
}InOut;
typedef struct {
char type; // transaction type, 'B' means buy, 'S' means sell.
unsigned int price;
unsigned int quantity;
} TransData;
// DDL - Doubly Linked List.
typedef struct _node {
TransData data;
struct _node *next, *prev;
}DDLNode;
typedef struct _list {
DDLNode *head, *tail;
}DDL;
DDLNode* CreateDDLNode(TransData *pData);
void ShowDDLNode(DDLNode *pNode);
void InitDDL(DDL *pddl);
bool IsEmptyDDL(DDL *pList);
bool IsHeadNode(DDL *pList, DDLNode *pNode);
bool IsTailNode(DDL *pList, DDLNode *pNode);
// DDDL - Descending DDL.
int InsertToDDDL(DDL *pList, TransData *pData);
void ShowDDLFromHead(DDL *pList, unsigned int cnt);
void ShowDDLFromTail(DDL *pList, unsigned int cnt);
#define CHECK_NULL_POINTER(ptr) \
if(!ptr){ \
fprintf(stderr, "null pointer at %s, line %d\n", __FUNCTION__, __LINE__); \
exit(-1); \
}
int main(){
InOut io = {0,0};
DDL sddl, bddl;
int i;
printf("Please input transactions count (in out):");
scanf(" %u %u", &io.in, &io.out);
//printf("io(%u, %u)\n", io.in, io.out);
printf("Please input the raw transaction data.\"('B' price quantity)\" for buying stocks, \"('S' price quantity)\" for selling stocks.\n");
TransData record[io.in];
for(i = 0; i < io.in; ){
scanf(" %c %u %u", &(record[i].type), &(record[i].price), &(record[i].quantity));
//printf("record[%d]:%c, %u, %u\n", i, record[i].type, record[i].price, record[i].quantity);
if(record[i].type != 'B' && record[i].type != 'S'){
printf("Wrong transaction type. It must be 'B' or 'S'!\n");
continue;
}
else{
++i;
}
}
InitDDL(&sddl);
InitDDL(&bddl);
for(i = 0; i < io.in; ++i){
//printf("\ninsert record[%d]: %c %u %u\n", i, record[i].type, record[i].price, record[i].quantity);
if(record[i].type == 'B'){
InsertToDDDL(&bddl, &(record[i]) );
}
else if(record[i].type == 'S'){
InsertToDDDL(&sddl, &(record[i]) );
}
}
printf("\noutput:\n");
ShowDDLFromTail(&sddl, io.out);
ShowDDLFromHead(&bddl, io.out);
return 0;
}
DDLNode* CreateDDLNode(TransData *pData){
DDLNode *pNewNode = (DDLNode *)malloc(sizeof(DDLNode));
CHECK_NULL_POINTER(pNewNode);
if(pData){
pNewNode->data.type = pData->type;
pNewNode->data.price = pData->price;
pNewNode->data.quantity = pData->quantity;
}
else{
pNewNode->data.type = 0;
pNewNode->data.price = 0;
pNewNode->data.quantity = 0;
}
pNewNode->next = NULL;
pNewNode->prev = NULL;
}
void ShowDDLNode(DDLNode *pNode){
if(pNode)
printf("%c %u %u %p %p %p\n", pNode->data.type, pNode->data.price, pNode->data.quantity, pNode, pNode->prev, pNode->next);
else
printf("null node\n");
}
void InitDDL(DDL *pList){
CHECK_NULL_POINTER(pList);
pList->head = NULL;
pList->tail = NULL;
}
bool IsEmptyDDL(DDL *pList){
CHECK_NULL_POINTER(pList);
return pList->head == NULL && pList->tail == NULL;
}
bool IsHeadNode(DDL *pList, DDLNode *pNode){
CHECK_NULL_POINTER(pList);
return pList->head == pNode;
}
bool IsTailNode(DDL *pList, DDLNode *pNode){
CHECK_NULL_POINTER(pList);
return pList->tail == pNode;
}
/*Function: create a new node to save data, and insert or merge it to descending DDL.
*@return value: 0 : success, -1 : fail.
*/
int InsertToDDDL(DDL *pList, TransData *pData){
CHECK_NULL_POINTER(pList);
if(IsEmptyDDL(pList) ){
DDLNode *pNewNode = CreateDDLNode(pData);
pList->head = pNewNode;
pList->tail = pNewNode;
return 0;
}
DDLNode *pNode = pList->head;
while(pNode){
if(pNode->data.price == pData->price){
pNode->data.quantity += pData->quantity;
return 0;
}
if(pNode->data.price < pData->price){
//Insert a new node before pNode.
DDLNode *pNewNode = CreateDDLNode(pData);
if(IsHeadNode(pList, pNode) ){
pNewNode->next = pNode;
pNode->prev = pNewNode;
pList->head = pNewNode;
return 0;
}
pNewNode->prev = pNode->prev;
pNode->prev->next = pNewNode;
pNewNode->next = pNode;
pNode->prev = pNewNode;
return 0;
}
if(pNode->data.price > pData->price){
if(IsTailNode(pList, pNode) ){
//Insert a new node after pNode.
DDLNode *pNewNode = CreateDDLNode(pData);
pNode->next = pNewNode;
pNewNode->prev = pNode;
pList->tail = pNewNode;
return 0;
}
pNode = pNode->next;
}
}
fprintf(stderr, "Fail to insert node to descending DDL.");
return -1;
}
void ShowDDLFromHead(DDL *pList, unsigned int cnt){
CHECK_NULL_POINTER(pList);
unsigned int i=0;
DDLNode *pNode = pList->head;
for(; i < cnt && pNode; ++i, pNode = pNode->next){
printf("%c %u %u\n", pNode->data.type, pNode->data.price, pNode->data.quantity);
}
}
void ShowDDLFromTail(DDL *pList, unsigned int cnt){
CHECK_NULL_POINTER(pList);
unsigned int i=0;
DDLNode *pNode = pList->tail;
for(; i < cnt && pNode; ++i, pNode = pNode->prev){
printf("%c %u %u\n", pNode->data.type, pNode->data.price, pNode->data.quantity);
}
}