题意:
给你一个字符串,问其子串中有多少个满足: 1.子串头尾字母不相同; 2.子串内部字母与头尾字母不相同; 3.子串长度大于等于2; 问有多少个这样的字串?
题目:
Leo has started a…
A. Do Not Be Distracted!
题意:
一件事情一但开始,只能做完才能做别的事,当出现一件事不连续出现时,教师会怀疑
题目:
Polycarp has 26 tasks. Each task is designated by a capital letter of the Latin alphab…