Grokking Binary Search for Coding Interviews_468 x 60 copy.png

Binary Search (BS) is, arguably, the most popular question in coding interviews. Even when you see that a problem can be solved with BS, it can be tricky to handle all of the indexes and base cases in the solution. What if there was an approach that could work for all BS problems? 
This course was designed from scratch with this one goal in mind. We'll explore one technique that can handle any BS problem. The practice problems in this course were carefully chosen to cover the most frequently asked BS questions in coding interviews. At the end of this course, you will feel confident to handle BS questions during phone or on-site interviews, as well as with all of the follow-ups about its time and space complexity.

Binary Search for Coding Interviews

# Problem statement

We'll call an array, `nums`, a **bitonic** array if the following properties hold:

-   $nums.length \geq 3$
-   There exists some  $i$  with $0 < i < nums.length - 1$ such that:
    -   $nums[0] < nums[1] < ... < nums[i-1] < nums[i]$.
    -   $nums[i] > nums[i+1] > ... > nums[nums.length - 1]$.

Suppose we are given an integer array `nums` that is __guaranteed__ to be a bitonic one, and return any `i` such that `nums[0] < nums[1] < ... < nums[i - 1] < nums[i] > nums[i + 1] > ... > nums[nums.length - 1]`.

**Constraints:**
-   $3 \leq nums.length \leq 10^4$
-   $0 \leq nums[i] \leq 10^6$
-   $nums$  is  **guaranteed**  to be a bitonic array.

**Example 1:**
```
Input: [0,1,0]    
Output: 1
```
**Example 2:**
```
Input: [0,2,1,0]    
Output: 1
```
**Example 3:**
```
Input: [0,10,5,2]    
Output: 1
```
**Example 4:**
```
Input: [3,4,5,1]    
Output: 2
```
**Example 5:**
```
Input: [24,69,100,99,79,78,67,36,26,19]    
Output: 2
```

Let's use our approach in a problem with an unsorted array as the input.

Difficulty Level: Easy

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Bitonic Point in Bitonic Array

Problem statement