Compilare: user.cpp: In function ‘void solve()’: user.cpp:29:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < s.size(); ++i) ~~^~~~~~~~~~ user.cpp:32:40: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int j = 1; j <= k && i+j-1 < s.size(); ++j) ~~~~~~^~~~~~~~~~ user.cpp:46:26: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int j = 0; j < s.size(); ++j) ~~^~~~~~~~~~ user.cpp:59:28: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int j = i-1; j < s.size(); ++j) ~~^~~~~~~~~~