/in/foo.cc: In function 'int main()':
/in/foo.cc:37:11: warning: unused variable 'r' [-Wunused-variable]
   int u,l,r,x;
           ^
/in/foo.cc:37:13: warning: unused variable 'x' [-Wunused-variable]
   int u,l,r,x;
             ^
/in/foo.cc:78:3: warning: 'flag' may be used uninitialized in this function [-Wmaybe-uninitialized]
   if(!flag) printf("No Solution\n");
   ^~