Compilare: user.cpp: In function ‘void calc(int)’: user.cpp:17:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<v[k].size();i++) ~^~~~~~~~~~~~ user.cpp: In function ‘int main()’: user.cpp:32:22: warning: unused variable ‘j’ [-Wunused-variable] int i,a,b,mn=N,k,j; ^ user.cpp:36:23: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(fi,"%d",&n); ^ user.cpp:39:32: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(fi,"%d%d",&a,&b); ^ user.cpp:56:14: warning: ‘k’ may be used uninitialized in this function [-Wmaybe-uninitialized] for(i=0;i<k;i++) ~^~