/tmp/ccW2HGk1.o: In function `main':
grader_encoder.cpp:(.text.startup+0x141): undefined reference to `encode(int, int*)'
collect2: error: ld returned 1 exit status
/tmp/ccTiOJ9i.o: In function `main':
grader_decoder.cpp:(.text.startup+0x1f6): undefined reference to `decode(int, int, int*)'
collect2: error: ld returned 1 exit status