2008秋-计算机软件基础- 第四章- 分块查找，索引顺序查找

//分块查找，索引顺序查找
#include<stdio.h>
//定义顺序存储线性表的结点结构
struct student

{

    long  Xuehao;//关键字
       int  Jihao; //非关键字
}; 

struct indexNode

{

    int address;

    int maxKey;

};
int SearchPosition(struct indexNode index[],int length, int someXuehao)

{

     int i;

    if(someXuehao<=index[0].maxKey)

        return index[0].address;


    if(someXuehao>=index[length-1].maxKey)

        return index[length-1].address;

    for(i=0;i<length-1;i++)

    {

         if(someXuehao>index[i].maxKey && someXuehao<=index[i+1].maxKey)

              return index[i+1].address;

    }

    return -1;

}

int SequencSearch(struct student students[],int startIndex,int length, int someXuehao)

{

 //顺序查找，在students[]中查找someXuehao，表长length 

 //成功返回位置（0~length-1）,失败返回-1。
    int i;

    for(i=startIndex;i<startIndex+length;i++)

    {

         if(students[i].Xuehao==someXuehao)

              return i;

    }

    return -1;

}

void main()

{

    struct student s[15]={1,11,2,22,3,33,4,44,5,55,

                          6,66,7,77,8,88,9,99,10,1000,

                            11,110,12,120,13,130,14,140,15,150};

    struct indexNode index[3]={0,5,5,10,10,15};


    int insertBlockIndex, searchPosition;

    insertBlockIndex=SearchPosition(index,3,16);

    printf("\ninsertBlockIndex：%d",insertBlockIndex);

    searchPosition=SequencSearch(s,insertBlockIndex,5,16);

    printf("\n下标为：%d\n",searchPosition);

}