Compilare: main.cpp: In function 'int main()': main.cpp:31:35: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int k = 0 ; k < v [j].size () ; ++ k) ~~^~~~~~~~~~~~~~~ main.cpp:35:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0 ; i < v [0].size () ; ++ i) ~~^~~~~~~~~~~~~~~ main.cpp:11:42: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen ("hamilton.in" , "r" , stdin); ^ main.cpp:12:44: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen ("hamilton.out" , "w" , stdout); ^ main.cpp:14:29: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf ("%d%d" , &n , &m); ^ main.cpp:20:40: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf ("%d%d%d" , &a , &b , &c); ^