学步园

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author ：Vange
create-time: 2010-03-10
http://hi.baidu.com/romeroad/blog/item/8aa0efc4c6f473c038db496c.html

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在大学的时候，曾经觉得这个算法是多么的不可思议，觉得计算机真的很了不起，我都无法去递归相像它。同时递归原来还可以改为非递归。这样对空间的把握就更好了。就说递归进去后不一定需要一层一层出来。如果条件允许的话，可以直接跳转出来。呵呵，这就是可以改进的地方。

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#include <stdio.h><br /> int BinarySearch(int *arr, int n, int val) {<br /> int low,high,mid;<br /> low = 0, high = n - 1;<br /> while (low <= high) {<br /> mid = (low + high)/2;<br /> if(arr[mid] > val) high = mid - 1;<br /> else if (arr[mid] < val) low = mid + 1;<br /> else if (arr[mid] == val) return mid;<br /> }<br /> return -1;<br /> }<br /> main() {<br /> int ints[] = {11, 22, 33, 44, 55, 66};<br /> int *pArr = ints;<br /> int size = sizeof(ints)/sizeof(*ints); //刚学习的计算数组大小，但暂时没有发现更有用的地方<br /> printf(" the position of 11 is : %d /n", BinarySearch(pArr, size, 11));<br /> printf(" the position of 44 is : %d /n", BinarySearch(pArr, size, 44));<br /> printf(" the position of 25 is : %d /n", BinarySearch(pArr, size, 25));</p> <p>}<br />

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