摘要:
给字符串 s 然后 Q 次询问 字符串 t 是不是 s 的子序列 序列自动机是用来判断是否是子序列的算法 时间复杂度是 $O(len)$ nx[i][j] 数组存的是在 s 中第 i 位后面第一个 j 字母出现的位置 阅读全文
摘要:
A. Stock Arbitraging Welcome to Codeforces Stock Exchange! We're pretty limited now as we currently allow trading on one stock, Codeforces Ltd. We hop 阅读全文
摘要:
https://leetcode.com/problems/2-keys-keyboard/ Initially on a notepad only one character 'A' is present. You can perform two operations on this notepa 阅读全文
摘要:
https://leetcode.com/problems/student-attendance-record-ii/ Given a positive integer n, return the number of all possible attendance records with leng 阅读全文