0_0_20784751_29045.cpp 0_0_20784751_29045.cpp(38) : error C3861: “__gcd”: 找不到标识符 0_0_20784751_29045.cpp(45) : error C3861: “__gcd”: 找不到标识符 0_0_20784751_29045.cpp(47) : error C3861: “__gcd”: 找不到标识符