数据结构-折半查找

折半查找仅适用于排序数组的情况

#include<iostream>

 

using namespace std;

 

int BinarySearch(int* a,const int x,const int n);

 

int main()

{

    int x[]={1,2,3,4,5,6,7,8,9,10};

    int result;

    int num=7;

    result=BinarySearch(x,num,10);

    if(result<0)

            cout<<"没找到"<<endl;

    else

        cout<<"在 x["<<result<<"]找到"<<num<<endl;

    return 0;

}

 

int BinarySearch(int* a,const int x,const int n)

{

    int low,high,mid;

    low=0;

    high=n-1;

    

    while(low<=high)

    {

        mid=(low+high)/2;

        if(a[mid]==x)

            return mid;

        else if(a[mid]<x)

            low=mid+1;

        else if(a[mid]>x)

            high=mid-1;

    }

    return -1;

}