数据结构基础(2) --顺序查找 ; 二分查找

//实现  
template <typename Type>  
Type *sequenceSearch(Type *begin, Type *end, const Type &searchValue)  
throw(std::range_error)  
{  
    if ((begin == end) || (begin == NULL) || (end == NULL))  
        throw std::range_error("pointer unavailable");  
    for (Type *index = begin; index < end; ++index)  
    {  
        if (*index == searchValue)  
            return index;  
    }  
    return end;  
}  
template <typename Type>  
Type *sequenceSearch(Type *array, int length, const Type &searchValue)  
throw(std::range_error)  
{  
    return sequenceSearch(array, array+length, searchValue);  
}  

//实现:迭代二分  
template <typename Type>  
Type *binarySearch(Type *begin, Type *end, const Type &searchValue)  
throw(std::range_error)  
{  
    if ((begin == end) || (begin == NULL) || (end == NULL))  
        throw std::range_error("pointer unavailable");  
    /**注意:此处high为end-1,并不是end 
        因为在后续的查找过程中,可能会如下操作 (*high), 或等价的操作 
        此时应该访问的是最后一个元素, 必须注意不能对数组进行越界访问! 
    */  
    Type *low = begin, *high = end-1;  
    while (low <= high)  
    {  
        //计算中间元素  
        Type *mid = low + (high-low)/2;  
        //如果中间元素的值==要找的数值, 则直接返回  
        if (*mid == searchValue)  
            return mid;  
        //如果要找的数比中间元素大, 则在数组的后半部分查找  
        else if (searchValue > *mid)  
            low = mid + 1;  
        //如果要找的数比中间元素小, 则在数组的前半部分查找  
        else  
            high = mid - 1;  
    }  
    return end;  
}  
template <typename Type>  
Type *binarySearch(Type *array, int length, const Type &searchValue)  
throw(std::range_error)  
{  
    return binarySearch(array, array+length, searchValue);  
}  
递归简介
 递归就是递归...(自己调用自己),递归的是神,迭代的是人;
递归与非递归的比较
[cpp] view plain copy 在CODE上查看代码片派生到我的代码片
//递归求解斐波那契数列  
unsigned long ficonacciRecursion(int n)  
{  
    if (n == 1 || n == 2)  
        return 1;  
    else  
        return ficonacciRecursion(n-1) + ficonacciRecursion(n-2);  
}  

//非递归求解斐波那契数列  
unsigned long ficonacciLoop(int n)  
{  
    if (n == 1 || n == 2)  
        return 1;  
    unsigned long  first = 1, second = 1;  
    unsigned long  ans = first + second;  
    for (int i = 3; i <= n; ++i)  
    {  
        ans = first + second;  
        first = second;  
        second = ans;  
    }  
    return ans;  
}  

//实现  
template <typename Type>  
Type *binarySearchByRecursion(Type *front, Type *last, const Type &searchValue)  
throw(std::range_error)  
{  
    if ((front == NULL) || (last == NULL))  
        throw std::range_error("pointer unavailable");  
    if (front <= last)  
    {  
        Type *mid = front + (last-front)/2;  
        if (*mid == searchValue)  
            return mid;  
        else if (searchValue > *mid)  
            return binarySearchByRecursion(mid+1, last, searchValue);  
        else  
            return binarySearchByRecursion(front, mid-1, searchValue);  
    }  
    return NULL;  
}  
template <typename Type>  
int binarySearchByRecursion(Type *array, int left, int right, const Type &searchValue)  
throw (std::range_error)  
{  
    if (array == NULL)  
        throw std::range_error("pointer unavailable");  
    if (left <= right)  
    {  
        int mid = left + (right-left)/2;  
        if (array[mid] == searchValue)  
            return mid;  
        else if (searchValue < array[mid])  
            return binarySearchByRecursion(array, left, mid-1, searchValue);  
        else  
            return binarySearchByRecursion(array, mid+1, right, searchValue);  
    }  
    return -1;  
}