Wrong Answer
/in/foo.cc: In function 'int dfs(int, int)':
/in/foo.cc:13:5: warning: suggest explicit braces to avoid ambiguous 'else' [-Wparentheses]
if (l+1==r)
^
/in/foo.cc: In function 'int dfs(int, int)':
/in/foo.cc:13:5: warning: suggest explicit braces to avoid ambiguous 'else' [-Wparentheses]
if (l+1==r)
^
