704.py

'''
Given an array of integers nums which is sorted in ascending order, and an integer target, write a function to search target in nums. If target exists, then return its index. Otherwise, return -1.

You must write an algorithm with O(log n) runtime complexity.

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

Constraints:

1 <= nums.length <= 104
-104 < nums[i], target < 104
All the integers in nums are unique.
nums is sorted in ascending order.
'''

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

import unittest

def search(nums, target):
    left, right = 0, len(nums) - 1
    while left <= right:
        mid = left + (right - left) // 2
        if nums[mid] == target:
            return mid
        elif nums[mid] < target:
            left = mid + 1
        else:
            right = mid - 1
    return -1

class TestBinarySearch(unittest.TestCase):
    def test_example1(self):
        nums = [-1, 0, 3, 5, 9, 12]
        target = 9
        expected = 4
        # Call the function that solves the problem
        result = search(nums, target)
        # Assert that the result matches the expected output
        self.assertEqual(result, expected)

    def test_example2(self):
        nums = [-1, 0, 3, 5, 9, 12]
        target = 2
        expected = -1
        # Call the function that solves the problem
        result = search(nums, target)
        # Assert that the result matches the expected output
        self.assertEqual(result, expected)

if __name__ == '__main__':
    unittest.main()