版权声明:本文为博主原创文章,未经博主允许不得转载。 https://blog.csdn.net/hsx1612727380/article/details/86215700
Title:Binary Search 704
Difficulty:Easy
原题leetcode地址: https://leetcode.com/problems/binary-search/
1. 二分法
时间复杂度:O(logn),一层while循环。
空间复杂度:O(n),没有申请ewai空间。
/**
* 二分法
* @param nums
* @param target
* @return
*/
public static int search(int[] nums, int target) {
if (target < nums[0] || target > nums[nums.length - 1]) {
return -1;
}
int low = 0;
int high = nums.length - 1;
while (low <= high) {
int mid = (low + high) / 2;
if (nums[mid] == target) {
return mid;
}
else if (nums[mid] < target) {
low = mid + 1;
}
else {
high = mid - 1;
}
}
return -1;
}