二分查找的三种写法

 1 public static int binary(int[] arr, int data)
 2 {
 3     int min=0;
 4     int max=arr.length-1;
 5     int mid;
 6     while(min<=max)
 7     {
 8         mid=(min + max)/2;
 9         if(arr[mid]>data)11             max=mid-1;13         else if(arr[mid]<data)15             min=mid+1;17         else19             return mid;21     }
22     return -1;
23 }

 1 public static int binary(int[] arr, int data)
 2 {
 3     int min=0;
 4     int max=arr.length-1;
 5     int mid;
 6     while(min<=max)
 7     {
 8         mid=min+(max-min)/2;// 防止溢出
 9         if(arr[mid]>data)
10             max = mid - 1;
11         else if (arr[mid] < data)
12             min = mid + 1;
13         else
14             return mid;
15     }
16     return -1;
17 }

 1 public static int binary(int[] arr, int data)
 2 {
 3     int min=0;
 4     int max=arr.length-1;
 5     int mid;
 6     while (min <= max)
 7     {
 8         mid=min+( (max - min)>>>1 );// 无符号位运算符的优先级较低，先括起来
 9         if(arr[mid]>data)
10             max = mid - 1;
11         else if(arr[mid]<data)
12             min = mid + 1;
13         else
14             return mid;
15     }
16     return -1;
17 }