If BRIGHTEN is written as HJSCMDSG. How is COMPLETE written in that code?

In this kind of letter-coding puzzle, the given example encodes a fixed rule that must be inferred by comparing each letter's position with its coded counterpart. A common pattern is to split the word into equal-length blocks, reverse the letters within each block, and then shift each block's letters forward or backward through the alphabet by a fixed number of steps -- often in opposite directions for different blocks.

Applying this to the given example, BRIGHTEN -> HJSCMDSG, confirms the exact rule, which is then applied to COMPLETE:

1. Split BRIGHTEN into two 4-letter blocks: BRIG and HTEN.

2. Reverse BRIG to get GIRB, then shift each letter forward by one position: G->H, I->J, R->S, B->C, giving HJSC -- this matches the first half of the coded word.

3. Reverse HTEN to get NETH, then shift each letter backward by one position: N->M, E->D, T->S, H->G, giving MDSG -- this matches the second half of the coded word, confirming the rule: first block reversed then shifted forward by one; second block reversed then shifted backward by one.

4. Apply the same rule to COMPLETE: split it into COMP and LETE.

5. Reverse COMP to get PMOC, then shift each letter forward by one position: P->Q, M->N, O->P, C->D, giving QNPD.

6. Reverse LETE to get ETEL, then shift each letter backward by one position: E->D, T->S, E->D, L->K, giving DSDK.

7. Combine the transformed blocks in the original word order (first block, then second block): QNPD + DSDK = QNPDDSDK.

Cross-check: reversing the transformation on QNPDDSDK -- shifting the first block's letters back by one position and reversing them, and shifting the second block's letters forward by one position and reversing them -- returns COMP and LETE respectively, confirming QNPDDSDK is the correct code for COMPLETE.