二分查找

来源：互联网发布：淘宝上的好评怎么写编辑：程序博客网时间：2024/06/15 02:44
 public class BinarySearch {         /**         * 二分查找算法         *         * @param srcArray 有序数组         * @param key 查找元素         * @return key的数组下标，没找到返回-1         */          public static void main(String[] args) {             int srcArray[] = {3,5,11,17,21,23,28,30,32,50,64,78,81,95,101};               System.out.println(binSearch(srcArray, 0, srcArray.length - 1, 81));          }         // 二分查找递归实现           public static int binSearch(int srcArray[], int start, int end, int key) {               int mid = (end - start) / 2 + start;               if (srcArray[mid] == key) {                   return mid;               }               if (start >= end) {                   return -1;               } else if (key > srcArray[mid]) {                   return binSearch(srcArray, mid + 1, end, key);               } else if (key < srcArray[mid]) {                   return binSearch(srcArray, start, mid - 1, key);               }               return -1;           }         // 二分查找普通循环实现           public static int binSearch(int srcArray[], int key) {               int mid = srcArray.length / 2;               if (key == srcArray[mid]) {                   return mid;               }               int start = 0;               int end = srcArray.length - 1;               while (start <= end) {                   mid = (end - start) / 2 + start;                   if (key < srcArray[mid]) {                      end = mid - 1;                   } else if (key > srcArray[mid]) {                       start = mid + 1;                   } else {                       return mid;                   }               }               return -1;           }     }
0 0