# Linear Search

Given an arbitrary sequence `S`

with `n`

elements, the problem of search is to find the position of a given element `e`

in `S`

or assert its absence.

If there is no additional information about the sequence `S`

, there is no better approach than visiting every element of `S`

, which might as well be done in sequence order.

Naturally, linear search has `O(n)`

complexity, with respect to the number of elements `n`

of `S`

.

def linear_search(arr, e): for i in range(len(arr)): if arr[i] == e: return i return -1 # sentinel value for "not found"