循环有序数组查找一个数

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网上看了有些代码有些错误，主要是下面实例中的0查找不到，这里重新更正了下

思想：循环数组有一边是有序的，首先先判断哪一边有序（通过将当前mid点与最左边节点比较），然后查看是否在有序边上

代码如下

#include<iostream>#include<assert.h>using namespace std;int Binary_Search(int *a,int low,int high,int value){int mid=(low+high)/2;if(a[mid] == value)return mid;    if(a[mid]>=a[low])       //左有序    {        if(a[low]<=value && value<a[mid])        //说明value在左边，直接二分查找        {            return Binary_Search(a,low,mid,value);        }        else                                       //value在右边        {            return Binary_Search(a,mid+1,high,value);        }    }    else                    //右有序    {        if(a[mid]<=value && value<=a[high])        {            return Binary_Search(a,mid,high,value);        }        else        {            return Binary_Search(a,low,mid-1,value);        }}}int main(){int A[10] = {7,8,9,0,1,2,3,4,5,6};int p = Binary_Search(A,0,9,0);cout<<p<<endl;return 0;}

非递归写法如下：

#include<iostream>#include<stdio.h>#include<assert.h>using namespace std;int Binary_Search(int *A,int size,int value){assert(A != NULL);int low = 0;int high = size - 1;while(low <= high){int mid = (low + high) / 2;if(A[mid] == value)return mid;if(A[low] <= A[mid])//左有序,注意‘=’的使用{if(A[low] <= value && value <= A[mid])high = mid - 1;else low = mid + 1;}else//右有序{if(A[mid] <= value && A[high] >= value)low = mid + 1;elsehigh = mid - 1;}}}int main(){int A[10] = {7,8,9,0,1,2,3,4,5,6};cout<<Binary_Search(A,10,5);return 0;}

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