/in/foo.c:1:4: error: 'L1' undeclared here (not in a function)
 DP[L1,L2,R1,R2]:=SUM[L2,R1]+A[L1]+A[R2]-MIN{DP[L1,L2+1,R1,R2],DP[L1,L2,R1-1,R2],DP[L2,L2+1,R1,R2],DP[L1,L2,R1-1,R1]}
    ^~
/in/foo.c:1:6: error: expected ']' before ',' token
 DP[L1,L2,R1,R2]:=SUM[L2,R1]+A[L1]+A[R2]-MIN{DP[L1,L2+1,R1,R2],DP[L1,L2,R1-1,R2],DP[L2,L2+1,R1,R2],DP[L1,L2,R1-1,R1]}
      ^