Compilare: user.cpp: In function ‘int main()’: user.cpp:22:43: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for( int j = 0; j < v[a].size(); j++ ){ ^ user.cpp:29:43: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for( int j = 0; j < v[b].size(); j++ ){ ^ user.cpp:45:39: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for( int j = 0; j < v[i].size(); j++ ){ ^ user.cpp:9:34: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf( fin, "%d%d", &k, &n ); ^