Compilare: user.cpp: In function ‘int main()’: user.cpp:16:17: warning: suggest parentheses around ‘-’ inside ‘<<’ [-Wparentheses] s+=(1<<i-1)*(N-i+1); ^ user.cpp:51:13: warning: unused variable ‘i’ [-Wunused-variable] int i=N,j=S-s2; ^ user.cpp:51:17: warning: unused variable ‘j’ [-Wunused-variable] int i=N,j=S-s2; ^