摘要： https://codeforces.com/problemset/problem/1787/C This is the reason why the problem was named as Remove the Bracket. \begin{aligned} \text{Product} &= 閱讀全文

摘要： https://codeforces.com/contest/1741/problem/E Let's introduce the dynamics. ${\displaystyle dp[i]=true}$ if on the prefix ii the answer is Yes. Then i 閱讀全文