View Compilation Error

0_0_19749522_28575.cpp: In function 'void init()':
0_0_19749522_28575.cpp:15:33: error: 'memset' was not declared in this scope
      memset(ffa, -1, sizeof(ffa));     
                                 ^
0_0_19749522_28575.cpp: In function 'bool SPFA(int, int, int)':
0_0_19749522_28575.cpp:30:33: error: 'memset' was not declared in this scope
      memset(pre, -1, sizeof(pre));
                                 ^