二分查找

static boolean binarySearch(int target, int[] array) { 

17         int front = 0; 

18         int tail = array.length - 1; 

19         // 判断子数组是否能再次二分 

20         while (front <= tail) { 

21             // 获取子数组的中间位置，并依据此中间位置进行二分 

22             int middle = (front + tail) / 2; 

23   

24             if (array[middle] == target) { 

25                 return true; 

26             } else if (array[middle] > target) { 

27                 tail = middle - 1; 

28             } else { 

29                 front = middle + 1; 

30             } 

31         } 

32         return false; 

33     }