Compilare: main.cpp: In function 'int main()': main.cpp:13:30: warning: unused variable 'y' [-Wunused-variable] long long n,x=0,i,j,m1,t,y=0,r; ^ main.cpp:16:13: warning: iteration 40000 invokes undefined behavior [-Waggressive-loop-optimizations] v[i]=0; ~~~~^~ main.cpp:15:16: note: within this loop for (i=1; i<=40001; i++) ~^~~~~~~ main.cpp:39:14: warning: 'r' may be used uninitialized in this function [-Wmaybe-uninitialized] r+=v[i]*v[j]; ~^~~~~~~~~~~