In file included from c:\mingw\lib\gcc\mingw32\4.8.1\include\c++\cmath:44:0,
from c:\mingw\lib\gcc\mingw32\4.8.1\include\c++\random:38,
from c:\mingw\lib\gcc\mingw32\4.8.1\include\c++\bits\stl_algo.h:65,
from c:\mingw\lib\gcc\mingw32\4.8.1\include\c++\algorithm:62,
from foo.cpp:6:
c:\mingw\include\math.h: In function 'float hypotf(float, float)':
c:\mingw\include\math.h:635:30: error: '_hypot' was not declared in this scope
{ return (float)(_hypot (x, y)); }

代码加上#include <algorithm>就会CE，去掉就AC了。。
这什么情况？？https://vijos.org/p/1124 这一题【貌似是编译参数的问题？
窝的Rp啊，窝的Rp啊，窝的Rp啊