View Compilation Error

0_0_22075171_19512.cpp:25:15: error: 'CLOCKS_PER_SEC' was not declared in this scope
 int LIM = 0 * CLOCKS_PER_SEC; 
               ^
0_0_22075171_19512.cpp: In function 'void dfs(int, int, int)':
0_0_22075171_19512.cpp:127:23: error: 'clock' was not declared in this scope
             if (clock() - ST > LIM)
                       ^
0_0_22075171_19512.cpp: In function 'int main()':
0_0_22075171_19512.cpp:141:20: error: 'clock' was not declared in this scope
         ST = clock();
                    ^