[ABC306C] Centers 题目分析： 用一个标记数组储存每个数出现的次数， 当第二次出现时用记录权值…
[ABC306E] Best Performances 题目大意： 有一个长度为 n 的序列，最开始都是 0。…
[ABC307_D] Mismatched Parentheses 题目分析 对于一个给定字符串删出每对括号里…
$$求:\frac{1}{m^n} \cdot \sum_{i=1}^{n} i^k \cdot f(i) $…
![[ABC306C] Centers](https://tarjan.me/wp-content/themes/wordpress-theme-puock-2.8.8/timthumb.php?w=280&h=160&a=c&zc=1&q=90&src=https://tarjan.me/wp-content/themes/wordpress-theme-puock-2.8.8/assets/img/random/4.jpg "[ABC306C] Centers")
![[ABC306E] Best Performances](https://tarjan.me/wp-content/themes/wordpress-theme-puock-2.8.8/timthumb.php?w=280&h=160&a=c&zc=1&q=90&src=https://tarjan.me/wp-content/themes/wordpress-theme-puock-2.8.8/assets/img/random/2.jpg "[ABC306E] Best Performances")
![[ABC307_D] Mismatched Parentheses](https://tarjan.me/wp-content/themes/wordpress-theme-puock-2.8.8/timthumb.php?w=280&h=160&a=c&zc=1&q=90&src=https://tarjan.me/wp-content/themes/wordpress-theme-puock-2.8.8/assets/img/random/5.jpg "[ABC307_D] Mismatched Parentheses")
