二分搜索方法

int binarySearch(int list[], int key, int low, int high){int mid;while(low <= high){int mid = (low + high)/2;if (key == list[mid])return mid;else if(key < list[mid])high = mid - 1;elselow = mid + 1;}if (key > list[mid]){return mid+1;}else return mid;}

PS:list中的数组是由小到大有序存放的。

另外讨论一种错误的二分搜索法：

int binarySearch(int list[], int key, int low, int high){int mid;while(low <= high){int mid = (low + high)/2;if (key == list[mid])return mid;else if(key < list[mid])high = mid - 1;elselow = mid ;}if (key > list[mid]){return mid+1;}else return mid;}

这种情况在最后会陷入low=mid的死循环。