Problem 45256. List one vertex neighbors

First input T is a triangulation connectivity indices list (triplet list of indices -positive integers-, each index refering to a vertex number in a corresponding vertices list).
Second input i is a vertex index (positive integer).
The purpose of this function is to query the list L of all i neighbor indices.
For instance if
T = [1 2 4;...
2 3 4;...
5 6 8;...
6 7 8;...
1 2 5;...
2 5 6;...
2 3 6;...
3 6 7;...
3 4 7;...
4 7 8;...
4 1 8;...
1 8 5]
and i = 3, then the function should return
L = [2, 4, 6, 7]
since 2, 4, 6, and 7 are all part of triangles / rows in which 3 is also a vertex member.
Hypothesis :
- Output L doesn't need to be ordered, but must not contain duplicated index.
- Output L is a row vector , and if the vertex index is not in the list , the function must of course return the empty set, [].
See also
Solve

Solution Stats

67.44% Correct | 32.56% Incorrect
Last Solution submitted on Nov 18, 2025

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