Problem	trains
User	benji9736
Submission Time	2026-01-01 18:22:10
Score	0
Max Time	N/A
Max Memory	N/A

Compile Error

trains.cpp: In function ‘int main()’:
trains.cpp:22:32: error: ‘M’ was not declared in this scope
22 | vector<vector<int>> bucket(M);
| ^