第十三周项目1验证算法

1、认真阅读并验证折半查找算法。请用有序表{12,18,24,35,47,50,62,83,90,115,134}作为测试序列，分别对查找90、47、100进行测试。

1. 折半查找

#include <stdio.h>#define MAXL 100typedef int KeyType;typedef char InfoType[10];typedef struct{    KeyType key;                //KeyType为关键字的数据类型    InfoType data;              //其他数据} NodeType;typedef NodeType SeqList[MAXL];     //顺序表类型int BinSearch(SeqList R,int n,KeyType k){    int low=0,high=n-1,mid;    while (low<=high)    {        mid=(low+high)/2;        if (R[mid].key==k)      //查找成功返回            return mid+1;        if (R[mid].key>k)       //继续在R[low..mid-1]中查找            high=mid-1;        else            low=mid+1;          //继续在R[mid+1..high]中查找    }    return 0;}int main(){    int i,n=10;    int result;    SeqList R;    KeyType a[]= {1,3,9,12,32,41,45,62,75,77},x=75;    for (i=0; i<n; i++)        R[i].key=a[i];    result = BinSearch(R,n,x);    if(result>0)        printf("序列中第 %d 个是 %d\n",result, x);    else        printf("木有找到！\n");    return 0;}
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2.递归的折半查找算法

#include <stdio.h>#define MAXL 100typedef int KeyType;typedef char InfoType[10];typedef struct{    KeyType key;                //KeyType为关键字的数据类型    InfoType data;              //其他数据} NodeType;typedef NodeType SeqList[MAXL];     //顺序表类型int BinSearch1(SeqList R,int low,int high,KeyType k){    int mid;    if (low<=high)      //查找区间存在一个及以上元素    {        mid=(low+high)/2;  //求中间位置        if (R[mid].key==k) //查找成功返回其逻辑序号mid+1            return mid+1;        if (R[mid].key>k)  //在R[low..mid-1]中递归查找            BinSearch1(R,low,mid-1,k);        else              //在R[mid+1..high]中递归查找            BinSearch1(R,mid+1,high,k);    }    else        return 0;}int main(){    int i,n=10;    int result;    SeqList R;    KeyType a[]= {1,3,9,12,32,41,45,62,75,77},x=75;    for (i=0; i<n; i++)        R[i].key=a[i];    result = BinSearch1(R,0,n-1,x);    if(result>0)        printf("序列中第 %d 个是 %d\n",result, x);    else        printf("木有找到！\n");    return 0;}

 2、认真阅读并验证分块查找算法。请用22,4,23,11,20,2,15,13,30,45,26,34,29,35,26,36,55,98,56, 74,61,90,80,96,127,158,116,114,128,113,115,102,184,211,243,188,187,218,195,210,279,307,492,452,408,361,421,399,856,523,704,703,697,535,534,739(共n=56个数据，每块数据个数s=8)作为数据表，自行构造索引表，分别对查找61、739、200进行测试。

 

分块查找

#include <stdio.h>#define MAXL 100    //数据表的最大长度#define MAXI 20     //索引表的最大长度typedef int KeyType;typedef char InfoType[10];typedef struct{    KeyType key;                //KeyType为关键字的数据类型    InfoType data;              //其他数据} NodeType;typedef NodeType SeqList[MAXL]; //顺序表类型typedef struct{    KeyType key;            //KeyType为关键字的类型    int link;               //指向对应块的起始下标} IdxType;typedef IdxType IDX[MAXI];  //索引表类型int IdxSearch(IDX I,int m,SeqList R,int n,KeyType k){    int low=0,high=m-1,mid,i;    int b=n/m;              //b为每块的记录个数    while (low<=high)       //在索引表中进行二分查找,找到的位置存放在low中    {        mid=(low+high)/2;        if (I[mid].key>=k)            high=mid-1;        else            low=mid+1;    }    //应在索引表的high+1块中,再在线性表中进行顺序查找    i=I[high+1].link;    while (i<=I[high+1].link+b-1 && R[i].key!=k) i++;    if (i<=I[high+1].link+b-1)        return i+1;    else        return 0;}int main(){    int i,n=25,m=5,j;    SeqList R;    IDX I= {{14,0},{34,5},{66,10},{85,15},{100,20}};    KeyType a[]= {8,14,6,9,10,22,34,18,19,31,40,38,54,66,46,71,78,68,80,85,100,94,88,96,87};    KeyType x=85;    for (i=0; i<n; i++)        R[i].key=a[i];    j=IdxSearch(I,m,R,n,x);    if (j!=0)        printf("%d是第%d个数据\n",x,j);    else        printf("未找到%d\n",x);    return 0;}