704.py

# Binary Search
# 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.
# 1. Input: nums = [-1,0,3,5,9,12], target = 9, Output: 4
# Explanation: 9 exists in nums and its index is 4
# 2. Input: nums = [-1,0,3,5,9,12], target = 2, Output: -1
# Explanation: 2 does not exist in nums so return -1

# worst case time complexity
# for i in range(len(nums)):
# if target == nums[i]:
# return i
# return -1

from typing import List
class Solution:
    def search(self, nums: list[int], target: int):
        low = 0
        high = len(nums) - 1

        while low <= high:
            mid = (low + high) // 2

            if target == nums[mid]:
                return mid
            elif target < nums[mid]:
                high = mid - 1
            elif target > nums[mid]:
                low = mid + 1
        return -1

solution = Solution()
result = solution.search([-1, 0, 3, 5, 9, 12], 9)
print(result)