[704] Binary Search

https://leetcode.com/problems/binary-search/description/

• algorithms
• Easy (41.20%)
• Source Code: 704.binary-search.py
• Total Accepted: 42.6K
• Total Submissions: 91.2K
• Testcase Example: '[-1,0,3,5,9,12]\n9'

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].

class Solution(object):
    def search(self, nums, target):
        """
        :type nums: List[int]
        :type target: int
        :rtype: int
        """
        if not nums: return -1
        lenn = len(nums)
        l, r = 0, lenn - 1
        while l <= r:
            mid = (l + r) / 2
            if nums[mid] == target: return mid
            elif nums[mid] > target:
                r = mid - 1
            else:
                l = mid + 1

        return -1