c-gcc, 123 bytes

Result

AC

Duration

539ms

Code [DL]

i;X[15];main(s){for(;~scanf("%d",X+i+3);)s-=i/9*(X[i]-=X[i+3])*(X[++i%3+3]*X[6-~i%3]-X[i%3+6]*X[3-~i%3]);printf("%d",s/6);}

stdin

67 87 79
32 30 05
05 03 62
26 76 21

stdout

34276

stderr

/tmp/code.c:1:1: warning: data definition has no type or storage class
 i;X[15];main(s){for(;~scanf("%d",X+i+3);)s-=i/9*(X[i]-=X[i+3])*(X[++i%3+3]*X[6-~i%3]-X[i%3+6]*X[3-~i%3]);printf("%d",s/6);}
 ^
/tmp/code.c:1:1: warning: type defaults to 'int' in declaration of 'i' [-Wimplicit-int]
/tmp/code.c:1:3: warning: data definition has no type or storage class
 i;X[15];main(s){for(;~scanf("%d",X+i+3);)s-=i/9*(X[i]-=X[i+3])*(X[++i%3+3]*X[6-~i%3]-X[i%3+6]*X[3-~i%3]);printf("%d",s/6);}
   ^
/tmp/code.c:1:3: warning: type defaults to 'int' in declaration of 'X' [-Wimplicit-int]
/tmp/code.c:1:9: warning: return type defaults to 'int' [-Wimplicit-int]
 i;X[15];main(s){for(;~scanf("%d",X+i+3);)s-=i/9*(X[i]-=X[i+3])*(X[++i%3+3]*X[6-~i%3]-X[i%3+6]*X[3-~i%3]);printf("%d",s/6);}
         ^~~~
/tmp/code.c: In function 'main':
/tmp/code.c:1:9: warning: type of 's' defaults to 'int' [-Wimplicit-int]
/tmp/code.c:1:23: warning: implicit declaration of function 'scanf' [-Wimplicit-function-declaration]
 i;X[15];main(s){for(;~scanf("%d",X+i+3);)s-=i/9*(X[i]-=X[i+3])*(X[++i%3+3]*X[6-~i%3]-X[i%3+6]*X[3-~i%3]);printf("%d",s/6);}
                       ^~~~~
/tmp/code.c:1:23: warning: incompatible implicit declaration of built-in function 'scanf'
/tmp/code.c:1:23: note: include '<stdio.h>' or provide a declaration of 'scanf'
/tmp/code.c:1:67: warning: operation on 'i' may be undefined [-Wsequence-point]
 i;X[15];main(s){for(;~scanf("%d",X+i+3);)s-=i/9*(X[i]-=X[i+3])*(X[++i%3+3]*X[6-~i%3]-X[i%3+6]*X[3-~i%3]);printf("%d",s/6);}
                                                                   ^~~
/tmp/code.c:1:67: warning: operation on 'i' may be undefined [-Wsequence-point]
/tmp/code.c:1:67: warning: operation on 'i' may be undefined [-Wsequence-point]
/tmp/code.c:1:67: warning: operation on 'i' may be undefined [-Wsequence-point]
/tmp/code.c:1:67: warning: operation on 'i' may be undefined [-Wsequence-point]
/tmp/code.c:1:67: warning: operation on 'i' may be undefined [-Wsequence-point]
/tmp/code.c:1:67: warning: operation on 'i' may be undefined [-Wsequence-point]
/tmp/code.c:1:106: warning: implicit declaration of function 'printf' [-Wimplicit-function-declaration]
 i;X[15];main(s){for(;~scanf("%d",X+i+3);)s-=i/9*(X[i]-=X[i+3])*(X[++i%3+3]*X[6-~i%3]-X[i%3+6]*X[3-~i%3]);printf("%d",s/6);}
                                                                                                          ^~~~~~
/tmp/code.c:1:106: warning: incompatible implicit declaration of built-in function 'printf'
/tmp/code.c:1:106: note: include '<stdio.h>' or provide a declaration of 'printf'

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