Explain linear search algorithm and its time complexity.

The linear search algorithm is a simple searching algorithm that sequentially checks each element in a list or array until a match is found or the end of the list is reached. It starts from the beginning of the list and compares each element with the target value until a match is found or the end of the list is reached.

The steps involved in the linear search algorithm are as follows:
1. Start from the first element of the list.
2. Compare the current element with the target value.
3. If the current element matches the target value, return the index of the element.
4. If the current element does not match the target value, move to the next element in the list.
5. Repeat steps 2-4 until a match is found or the end of the list is reached.
6. If the end of the list is reached without finding a match, return a "not found" indication.

The time complexity of the linear search algorithm is O(n), where n is the number of elements in the list. This means that the time taken to perform the search increases linearly with the size of the list. In the worst-case scenario, where the target value is not present in the list or is located at the end of the list, the algorithm will have to compare each element in the list, resulting in n comparisons. Therefore, the time complexity of the linear search algorithm is considered to be linear.