[LeetCode] Binary Search [Beat 100%]

Problem

Given a sorted (in ascending order) integer array nums of n elements and a target value, write a function to search target in nums. If target exists, then return its index, otherwise return -1.

Example 1:

Input: nums = [-1,0,3,5,9,12], target = 9
Output: 4
Explanation: 9 exists in nums and its index is 4

Example 2:

Input: nums = [-1,0,3,5,9,12], target = 2
Output: -1
Explanation: 2 does not exist in nums so return -1

Note:

You may assume that all elements in nums are unique.
n will be in the range [1, 10000].
The value of each element in nums will be in the range [-9999, 9999].

Beat 100%的要点：极简主义的参数名，不考虑溢出的中点初始化

Solution

class Solution {
    public int search(int[] nums, int target) {
        if (nums == null || nums.length == 0) return -1;
        int l = 0, r = nums.length-1;
        while (l <= r) {
            int m = (l+r)>>>1;
            if (nums[m] == target) return m;
            else if (nums[m] > target) r = m-1;
            else l = m+1;
        }
        return -1;
    }
}