/in/foo.cc: In function 'int build(int, int)':
/in/foo.cc:61:12: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
  int mid=le+ri>>1, t=++cnt;
          ~~^~~
/in/foo.cc: In function 'void zig(int)':
/in/foo.cc:87:5: warning: suggest explicit braces to avoid ambiguous 'else' [-Wparentheses]
  if (f2)
     ^
/in/foo.cc: In function 'void zag(int)':
/in/foo.cc:97:5: warning: suggest explicit braces to avoid ambiguous 'else' [-Wparentheses]
  if (f2)
     ^
/in/foo.cc: In function 'void splay(int)':
/in/foo.cc:120:5: warning: suggest explicit braces to avoid ambiguous 'else' [-Wparentheses]
  if (f1)
     ^