Problem 45259. Build edges list

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).
The purpose of this function is to query the list E of all the edges.
For instance if T = [1, 2, 3; 4, 5, 6; 7, 8, 9], then the output of the function must be E = [1, 2; 1, 3; 2, 3; 4, 5; 4, 6; 5, 6; 7, 8; 7, 9; 8, 9] (all the 3 possible combination of the 3 vertices of a triangle / row, for every triangle / row of the list).
Hypothesis on output E :
  • size(E) = [N, 2], with N the number of edges
  • E doesn't need to be ordered neither following dimension 1 (rows) nor dimension 2 (columns), but must not contain duplicated edges
  • Edges are symmetric : [e1, e2] is the same edge as [e2, e1]
  • Every indices are positive, distinct integers.
See also
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Solution Stats

75.38% Correct | 24.62% Incorrect
Last Solution submitted on Dec 07, 2025

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