Compilare: user.cpp: In function ‘void prim()’: user.cpp:40:32: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i<v[1].size(); ++i) ^ user.cpp:56:37: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<v[y].size();++i) ^ user.cpp: In function ‘void read()’: user.cpp:28:29: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d\n", &n, &m); ^ user.cpp:32:41: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d %d \n", &x, &y, &c); ^ user.cpp: In function ‘int main()’: user.cpp:72:34: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("apm.in", "r", stdin); ^ user.cpp:73:36: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("apm.out", "w", stdout); ^