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本篇博文没太多要说的,二分查找很简单,也是常见常考的查找算法,以下是递归非递归的实现。
非递归实现:
/*
非递归实现,返回对应的序号
*/
int BinarySearch(int *arr,int len,int key)
{
if(arr==NULL || len<1)
return -1;
int low = 0;
int high = len-1;
while(low <= high)
{
int mid = (low+high)>>1;
if(key == arr[mid])
return mid;
else if(key < arr[mid])
high = mid-1;
else
low = mid+1;
}
return -1;
}
递归实现:
/*
递归实现,返回对应的序号
*/
int BSearch(int *arr,int low,int high,int key)
{
if(arr==NULL || low>high)
return -1;
int mid = (low+high)>>1;
if(arr[mid] == key)
return mid;
else if(arr[mid] > key)
return BSearch(arr,low,mid-1,key);
else
return BSearch(arr,mid+1,high,key);
}
/*
将递归实现的方法封装起来
*/
int BinSearch(int *arr,int len,int key)
{
return BSearch(arr,0,len-1,key);
}