answer.code: In function ‘int min_cardinality(int)’:
answer.code:99:1: warning: control reaches end of non-void function [-Wreturn-type]
   99 | }
      | ^
/tmp/ccpp0Nnt.o: In function `move_outside(int)':
answer.code:(.text+0x1d0): multiple definition of `move_outside(int)'
/tmp/ccDxjrZB.o:implementer.cpp:(.text+0xd0): first defined here
/tmp/ccpp0Nnt.o: In function `move_inside(int)':
answer.code:(.text+0x2a0): multiple definition of `move_inside(int)'
/tmp/ccDxjrZB.o:implementer.cpp:(.text+0x0): first defined here
/tmp/ccpp0Nnt.o: In function `press_button()':
answer.code:(.text+0x320): multiple definition of `press_button()'
/tmp/ccDxjrZB.o:implementer.cpp:(.text+0x1a0): first defined here
collect2: error: ld returned 1 exit status