In the palindrome checker, which two variables are used as indices to compare mirrored characters?

• A. start and end
• B. left and right
• C. i and j
• D. head and tail

Answer: (B)

When checking a palindrome, you typically compare characters from both ends toward the center using two pointers. One pointer starts at the leftmost character, and the other starts at the rightmost character. After each comparison, you move the left pointer to the right and the right pointer to the left. This two-pointer setup directly mirrors the idea of comparing the first with the last, the second with the second-to-last, and so on, until the pointers meet or cross. Using the names left and right captures that opposite-end perspective, which is why they’re the natural choice for these indices.