CF DP a sentence to solve

Wyq said just start Oi or encounter bottlenecks when brush DP bar, although think so brush CF problem a little wasted, but still quite cool, according to solved sort, the front of the problem are quite water (forget record of the bastard), do not write, starting from 5C to write the problem

CF5 C. Longest Regular bracket Sequence: The main idea, give a sequence of parentheses, so that you find the longest legal expansion of the string, and the number of the oldest string of ideas: open a stack of mess, When the closing parenthesis is encountered, the longest length of the right parenthesis should be the length of the opening parenthesis plus the longest length of one character to the left of the left parenthesis.

CF DP a sentence to solve