View Compilation Error

0_0_37763434_23724.cpp: In function 'int main()':
0_0_37763434_23724.cpp:53:33: error: 'memset' was not declared in this scope
             memset(f,0,sizeof(f));        //每个分值卡堆对应的左偏树和卡片数初始化
                                 ^