View Compilation Error

0_0_26145106_17516.cpp: In function 'void init()':
0_0_26145106_17516.cpp:56:32: error: 'memset' was not declared in this scope
     memset(head,-1,sizeof(head));
                                ^
0_0_26145106_17516.cpp: In function 'int main()':
0_0_26145106_17516.cpp:103:17: error: expected ')' before 'if'
                 if (!DFN[i])
                 ^