Compilare: main.cpp: In function 'bool is_substring(int, int)': main.cpp:49:27: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 49 | for(int pos = sz; pos <= a[j].size(); pos++) { | ~~~~^~~~~~~~~~~~~~ main.cpp: In function 'int main()': main.cpp:72:26: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 72 | for(int j = 1; j <= a[i].size(); j++) { | ~~^~~~~~~~~~~~~~ In file included from /usr/include/c++/12.2.1/cassert:44, from /usr/include/c++/12.2.1/x86_64-pc-linux-gnu/bits/stdc++.h:33, from main.cpp:1: main.cpp:145:28: warning: comparison of integer expressions of different signedness: 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare] 145 | assert(answer_s.size() == answer); | ~~~~~~~~~~~~~~~~^~~~~~~~~