View Compilation Error

0_0_13812725_13900.cpp: In function 'void init_weight(int, int)':
0_0_13812725_13900.cpp:24:33: error: 'memset' was not declared in this scope
  memset(weight,-1,sizeof(weight));
                                 ^
0_0_13812725_13900.cpp: In function 'int fun(int, int)':
0_0_13812725_13900.cpp:67:33: error: 'memset' was not declared in this scope
  memset(father,-1,sizeof(father));
                                 ^