/in/foo.cc: In function 'int main()':
/in/foo.cc:25:8: warning: suggest explicit braces to avoid ambiguous 'else' [-Wparentheses]
      if(!b1&&!b2)
        ^
/in/foo.cc:32:29: warning: suggest parentheses around arithmetic in operand of '|' [-Wparentheses]
      else if(!b1&&b2)f[c][(k^(1<<(j-1))|(1<<j))<<1]+=f[c^1][k];
                            ~^~~~~~~~~~~