Given an image matrix, I want to find the pixel points coordinates of all points/pixels in the border of a given circle with center (x,y), where x and y are integers and radius r, where r is also an integer. Considering the border is 1 pixel thick. Ony this outer edge is what I need to find. I’m having …
Tag: algorithm
Find the indices where a sorted list of integer changes
Assuming a sorted list of integers as below: I want to find the indices where the values changes, i.e. One approach is to use itertools.groupby: Output This approach is O(n). Another possible approach is to use bisect.bisect_left: Output This approach is O(k*log n) where k is the number of distinct elements. …
How to generate more than one list from a list, using python functions
I am trying to make a 8 puzzle problem solver using different algorithms, such as BFS,DFS, A* etc. using python. For those who are not familiar with the problem, 8 puzzle problem is a game consisting of 3 rows and 3 columns. You can move the empty tile only horizontally or vertically, 0 represents the empty t…
What is Big O in this example of code, O(N) or O(N^2)?
Can you please explain what is Big O in this example of code? Answer It depends entirely on your definition of n. If you define n to be the number of cells in the 2d matrix, then this nested loop is of linear complexity O(n) in relation to it. On the other hand, if you define n to be the
How do you write a loop to merge 2 elements every N number of elements in a list?
I first took this data in a text file below: And I changed it into a list like this: I then removed everything with a colon. And my next step in the program below is to manually merge ‘second’ and ‘text’ and then ‘sec’ and ‘text’. This wont work in a program wit…
Appending item on same index
I have these indexes: [3,1,1,2] which shows position for every element in the first list And I need to append these items to that corresponding indexes: to list, to be like in this particular order, so after the item is inserted on the index and the next item is again pointing to the same position, the first …
Palindrome question use of lambda and key
Hey guys so I was working on this problem on the algoExpert platform, but I am struggling to understand what longest and currentLongest are really doing. Just from the beginning, I am not entirely sure what the currentLongest = [0, 1] is doing, is it just saying that it will have 2 values? Are odd and even re…
Finding MACD Divergence
I want to create a loop to automate finding MACD divergence with specific scenario/criterion, but I am finding it difficult to execute although its very easy to spot when looking at chart by eyes. Note: you can easily get this as ready available scanner but i want to improve my python knowledge, hope someone …
Can this algorithm be called insertion sort or is it some other algorithm?
I was curious that can this way of sorting be called insertion sort, there are a few differences between my code and the original implementation. In insertion sort, we pick the keys from the virtually ‘unsorted’ sub-array and compare it to the left subarray that is sorted. My code doesn’t do…
Most efficient way to determine lowest valid number within a big range by only knowing whether your guess is too low
Let’s assume you want to guess a certain number(x) within a big range in Python. A simple external validation function, which you can call as many times as needed, will give you hints: If the number being tested is equal to or higher than the lowest valid number, it will, in both cases, return True (you…