摘要：
//当时比赛的时候没有想到可以用SPFA做，TLE！ Problem Description Kelukin is a businessman. Every day, he travels around cities to do some business. On August 17th, in m 阅读全文
摘要：
You have two strings SS and TT in all capitals. Now an efficient program is required to maintain a operation and support a query. The operation C~i~ch 阅读全文
摘要：
Life is a journey, and the road we travel has twists and turns, which sometimes lead us to unexpected places and unexpected people. Now our journey of 阅读全文