class Solution {
/**
* 递归的二分查找
* @param nums
* @param target
* @param left
* @param right
* @return
*/
public int binarySearch(int[] nums, int target, int left, int right) {
if(left > right) {
return -1;
}
int midIndex = (int)(left + right) / 2 ;
if(target > nums[midIndex]) {
return binarySearch(nums, target, midIndex+1, right);
} else if(target < nums[midIndex]) {
return binarySearch(nums, target, left, midIndex-1);
} else {
return midIndex;
}
}
/**
* 非递归实现
* @param nums
* @param target
* @return
*/
public int binarySearchWithoutRecursion(int[] nums, int target) {
int low = 0;
int hight = nums.length -1;
while(low <= hight) {
int mid = (int) (low + hight) / 2;
if(nums[mid] == target) {
return mid;
} else if(target < nums[mid]){
hight = mid -1;
} else {
low = mid + 1;
}
}
return -1;
}
}原文：https://blog.51cto.com/janephp/2377440