Compilare: main.cpp: In function 'int main()': main.cpp:21:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < v.size(); i++){ ~~^~~~~~~~~~ main.cpp:22:26: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int j = 0; j < v.size(); j++){ ~~^~~~~~~~~~ main.cpp:23:30: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int k = 0; k < v.size(); k++){ ~~^~~~~~~~~~ main.cpp:31:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < v.size(); i++) ~~^~~~~~~~~~ main.cpp:33:26: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int j = 0; j < v.size(); j++) ~~^~~~~~~~~~ main.cpp:35:30: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int k = 0; k < v.size() && !ok; k++) ~~^~~~~~~~~~