Anyone knows a LeetCode problem showing Backtracking that abandons a candidate ("backtracks") as soon as it determines that the candidate cannot lead to a valid solution.

Below is quoted from the link below:

"Backtracking is a general algorithm for finding all (or some) solutions to some computational problems (notably Constraint satisfaction problems or CSPs), which incrementally builds candidates to the solution and abandons a candidate ("backtracks") as soon as it determines that the candidate cannot lead to a valid solution. [1] "
https://leetcode.com/explore/learn/card/recursion-ii/472/backtracking/2654/

Like the example 1 in the link above, but what does the code for the example look like in relation to Backtracking?

For example of the N-Queen II question, it seems the Backtracking is the " if is_valid(next_candidate)" below, not the "remove(next_candidate)" statement as mentioned on template below from https://leetcode.com/explore/learn/card/recursion-ii/472/backtracking/2793/

def backtrack(candidate):
if find_solution(candidate):
    output(candidate)
    return
# iterate all possible candidates.
for next_candidate in list_of_candidates:
    if is_valid(next_candidate):
        # try this partial candidate solution
        place(next_candidate)
        # given the candidate, explore further.
        backtrack(next_candidate)
        # backtrack
        remove(next_candidate)

		

What are your thoughts?