perm.cpp: In function 'std::vector<int> gen(std::vector<int>)':
perm.cpp:26:22: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
26 | for (int j = i; j < p.size(); j++) {
| ~~^~~~~~~~~~
perm.cpp: In function 'std::vector<int> construct_permutation(long long int)':
perm.cpp:39:2: warning: this 'if' clause does not guard... [-Wmisleading-indentation]
39 | if (!k) return p;
| ^~
perm.cpp:41:3: note: ...this statement, but the latter is misleadingly indented as if it were guarded by the 'if'
41 | vt.clear();
| ^~