Compilare: main.cpp: In function 'void solve()': main.cpp:91:22: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 91 | for(int i = 0; i < c.size(); i++) { | ~~^~~~~~~~~~ main.cpp: In instantiation of 'std::vector<int> FFT<FL>::mul(std::vector<int>, std::vector<int>) [with FL = double]': main.cpp:90:36: required from here main.cpp:56:28: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 56 | int n = 1; while(n < a.size() + b.size() + 1) n *= 2; | ~~^~~~~~~~~~~~~~~~~~~~~~~~~ main.cpp:60:18: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 60 | if(i < a.size()) x[i] = comp(a[i], 0); | ~~^~~~~~~~~~ main.cpp:61:18: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 61 | if(i < b.size()) y[i] = comp(b[i], 0); | ~~^~~~~~~~~~