by@kurgm
WA
549ms
X={} x=0 for i=-3,8 do X[i]=io.read"*n"-(X[i%3-3]or 0) p=-~i%3 q=~-i%3 x=x+i//6*X[i]*(X[p]*X[q+3]-X[q]*X[p+3]) end print(x//6)
23 69 35 86 03 50 95 96 42 75 02 78
/usr/bin/lua5.3: /volume/CODE:7: attempt to perform arithmetic on a nil value (field '?') stack traceback: /volume/CODE:7: in main chunk [C]: in ?