查找元素x，若x存在，则与其后继交换，否则将x插入，使顺序表有序

#include
#define LIST_INIT_SIZE 6
#define LISTINCREMENT 10
typedef int ElemType;
typedef struct{
	ElemType *elem;
	int length;
	int listsize;
}SqList;

void InitSqList(SqList *L);//初始化顺序表
void CreateSqList(SqList *L, ElemType *arr, int n);//给予顺序表初始数据
void ShowSqList(SqList *L);//输出顺序表数据

//二分法查找x，找到则返回元素索引，找不到则返回不大于x的最大元素索引的相反数
int SearchByElem(SqList *L, ElemType x);
//第i个数据之前插入x
void InsertByIndex(SqList *L, int i, ElemType x);
//交换数据值
void swap(ElemType *x, ElemType *y);
//查找元素x，若x存在，则与其后继交换，否则将x插入，使顺序表有序
void SearchSwapInsert(SqList *L, ElemType x);

int main()
{
	SqList L;
	ElemType arr[6] = { 1, 2, 3, 5, 7, 6 };
	
	InitSqList(&L);
	CreateSqList(&L, arr, 6);
	printf("初始数据列表：");
	ShowSqList(&L);
	printf("\n");

	printf("执行查找交换插入算法，数据为：%d\n",7);
	SearchSwapInsert(&L, 7);
	ShowSqList(&L);

	printf("执行查找交换插入算法，数据为：%d\n", 4);
	SearchSwapInsert(&L, 4);
	ShowSqList(&L);

	getchar();
	return 0;
}


void InitSqList(SqList *L)
{
	L->elem = (ElemType *)malloc(LIST_INIT_SIZE * sizeof(ElemType));
	L->length = 0;
	L->listsize = LIST_INIT_SIZE;
}

void CreateSqList(SqList *L, ElemType *arr, int n)
{
	int i;
	if (n <= LIST_INIT_SIZE)
	{
		for (i = 0; i < n; i++)
		{
			L->elem[i] = arr[i];
		}
		L->length = n;
	}
	else
	{
		printf("插入失败，数据个数应不大于 %d", LIST_INIT_SIZE);
	}
}

void ShowSqList(SqList *L)
{
	int i;
	for (int i = 0; i < L->length; i++)
	{
		printf(" %d ", L->elem[i]);
	}
	printf("\n");
}

//二分法查找x，找到则返回元素索引，找不到则返回不大于x的最大元素索引
int SearchByElem(SqList *L, ElemType x)
{
	int high = L->length - 1;
	int low = 0;
	int mid;
	while (low <= high)
	{
		mid = (high + low) / 2;
		if (L->elem[mid] == x)
		{
			return mid;
		}
		else if (x < L->elem[mid])
		{
			high = mid - 1;
		}
		else
		{
			low = mid + 1;
		}
	}
	//high为小于x元素集合中的最大值的索引
	return -high;
}

//第i个数据之前插入x
void InsertByIndex(SqList *L, int i, ElemType x)
{
	if (i<1||i>L->length+1)
	{
		printf("位置不合法，插入失败！");
		return;
	}
	if (L->length >= L->listsize)
	{
		ElemType *enew = (ElemType *)realloc(L->elem, (LISTINCREMENT + L->listsize) * sizeof(ElemType));
		L->elem = enew;
		L->listsize += LISTINCREMENT;
	}
	
	ElemType *p = &(L->elem[i - 1]);//待插入的位置
	ElemType *q = &(L->elem[L->length - 1]);//q指向最后一个元素
	for (; p <= q; q--)
	{
		*(q + 1) = *q;
	}
	*p = x;
	L->length++;
}

void swap(ElemType *x, ElemType *y)
{
	ElemType t = *y;
	*y = *x;
	*x = t;
}

void SearchSwapInsert(SqList *L, ElemType x)
{
	int k;
	if ((k = SearchByElem(L, x)) >= 0)
	{
		swap(&(L->elem[k]), &(L->elem[k + 1]));
	}
	else
	{
		InsertByIndex(L, -k + 2, x);
	}
}