Compilare: main.cpp: In function 'void katyusha()': main.cpp:117:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < pts.size(); ++i){ ~~^~~~~~~~~~~~ main.cpp: In function 'double erika()': main.cpp:131:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 1; i < shanp.size(); ++i){ ~~^~~~~~~~~~~~~~