Try to solve 6 C interview questions below. Hints can help you find answers to questions you are having trouble with.

**1. Palindrome**

A palindrome is a word that reads the same backward or forward.

Write a function that checks if a given word is a palindrome. Character case should be ignored. If the given word is a palindrome, the function should return 1; otherwise it should return 0.

For example, *is_palindrome("Deleveled")* should return *1* as character case should be ignored resulting with "deleveled" which is a palindrome since it reads same backward and forward.

- Example case: Wrong answer
- Lowercase words: Wrong answer
- Various words: Wrong answer

**2. Words**

Implement function *sort_words* that sorts an array of words that contain lowercase characters from english alphabet, in descending order, and is **efficient** with respect to time used.

For example, the array *{ "cherry", "orange", "apple" }* should, after sorting, become { "orange", "cherry", "apple" }.

- Example case: Wrong answer
- Several words: Wrong answer
- Performance test on a dictionary: Wrong answer

**3. Binary Search Tree**

Binary search tree (BST) is a binary tree where the value of each node is larger or equal to the values in all the nodes in that node's left subtree and smaller than the values in all the nodes in that node's right subtree.

Write a function that, **efficiently** with respect to time used, returns 1 if a given binary search tree contains a given value, else 0.

For example, for the following tree:

- n1 (Value: 1, Left: null, Right: null)
- n2 (Value: 2, Left: n1, Right: n3)
- n3 (Value: 3, Left: null, Right: null)

Call to *contains(&n2, 3)* should return 1 since a tree with root at n2 contains number 3.

- Example case: Wrong answer
- Correctness: Wrong answer
- Performance test on a large tree: Wrong answer

**4. Inspect Bits**

Implement the *inspect_bits* function that checks if given number contains 2 or more consecutive ones in its binary representation. If it does, the function should return *1*. Otherwise, it should return *0*.

For example, *inspect_bits(13)* should return *1* as it contains 2 consecutive ones in its binary representation (1101).

**5. Quadratic Equation**

Implement the function *find_roots* to find the roots of the quadratic equation: ax^{2} + bx + c = 0.

The roots of the quadratic equation can be found with the following formula:

For example, the roots of the equation 2x^{2} + 10x + 8 = 0 are -1 and -4.

**6. Watched Videos**

Implement the *count_views *function. It accepts an array of pointers to the *Viewer *struct, the size of the array, and the character array with the video name. It should return the number of *Viewers *who have watched a *Video* with the *name video_name*.

For example,

```
Video videos[] = { {.name = "Soccer", .unique_views = 500},
{.name = "Basketball", .unique_views = 1000} };
Viewer viewer = {.username = "Dave", .watched_videos = videos,
.watched_videos_size = 2};
Viewer *viewers[] = { &viewer };
```

calling *count_views(viewers, 1, "Soccer")* should return 1.

- Example case: Wrong answer
- Some people did not see the video: Wrong answer
- Various people and videos: Wrong answer

C Online Test (Easy)