Longest Palindromic Substring — DP table

Cell (i, j) answers "is s[i..j] a palindrome?" It's true when the ends match and the inside — cell (i+1, j−1) — is already true. Single letters start true.

Try:

single char = T empty substring = T (base) palindrome not / pending current (i,j) inside (i+1,j−1) longest so far