foo.cc: In function ‘int main()’:
foo.cc:8:15: warning: unused variable ‘s’ [-Wunused-variable]
    8 |     long long s=0;
      |               ^
foo.cc:17:21: warning: ‘*b[1]’ may be used uninitialized [-Wmaybe-uninitialized]
   17 |     int min=b[n]-b[1]-a[0]*(n-1);
      |                  ~~~^