c-gcc, 171 bytes

Result

AC

Duration

502ms

Code [DL]

main(y,z){int a[z=12];for(;z--;)scanf("%d",a+z);for(z=9;z--;)a[z]-=a[9+z%3];printf("%d",(a[7]*(a[3]*a[2]-*a*a[5])+a[6]*(a[1]*a[5]-a[4]*a[2])+a[8]*(*a*a[4]-a[3]*a[1]))/6);}

stdin

40 96 10
81 53 74
06 51 38
69 89 20

stdout

6467

stderr

/tmp/code.c:1:1: warning: return type defaults to 'int' [-Wimplicit-int]
 main(y,z){int a[z=12];for(;z--;)scanf("%d",a+z);for(z=9;z--;)a[z]-=a[9+z%3];printf("%d",(a[7]*(a[3]*a[2]-*a*a[5])+a[6]*(a[1]*a[5]-a[4]*a[2])+a[8]*(*a*a[4]-a[3]*a[1]))/6);}
 ^~~~
/tmp/code.c: In function 'main':
/tmp/code.c:1:1: warning: type of 'y' defaults to 'int' [-Wimplicit-int]
/tmp/code.c:1:1: warning: type of 'z' defaults to 'int' [-Wimplicit-int]
/tmp/code.c:1:33: warning: implicit declaration of function 'scanf' [-Wimplicit-function-declaration]
 main(y,z){int a[z=12];for(;z--;)scanf("%d",a+z);for(z=9;z--;)a[z]-=a[9+z%3];printf("%d",(a[7]*(a[3]*a[2]-*a*a[5])+a[6]*(a[1]*a[5]-a[4]*a[2])+a[8]*(*a*a[4]-a[3]*a[1]))/6);}
                                 ^~~~~
/tmp/code.c:1:33: warning: incompatible implicit declaration of built-in function 'scanf'
/tmp/code.c:1:33: note: include '<stdio.h>' or provide a declaration of 'scanf'
/tmp/code.c:1:77: warning: implicit declaration of function 'printf' [-Wimplicit-function-declaration]
 main(y,z){int a[z=12];for(;z--;)scanf("%d",a+z);for(z=9;z--;)a[z]-=a[9+z%3];printf("%d",(a[7]*(a[3]*a[2]-*a*a[5])+a[6]*(a[1]*a[5]-a[4]*a[2])+a[8]*(*a*a[4]-a[3]*a[1]))/6);}
                                                                             ^~~~~~
/tmp/code.c:1:77: warning: incompatible implicit declaration of built-in function 'printf'
/tmp/code.c:1:77: note: include '<stdio.h>' or provide a declaration of 'printf'

strace