永夜莫明的博客

链接：https://ac.nowcoder.com/acm/contest/992/J?&headNav=acm来源：牛客网题目描述红红和蓝蓝是随机降生在苹果树上的苹果仙灵，现在红线仙想估测他们的CP系数，并决定是否使他们成为一对CP。给出n个结点n-1条边的树，节点编号为1到n,定义distance(i,j)为i与j的树上距离。CP系数是指所有红红和蓝蓝在不同位置i,j的d...

https://cn.vjudge.net/contest/312853#problem/FNew Year is coming in Tree World! In this world, as the name implies, there arencities connected byn - 1roads, and for any two distinct cities there ...

链接：https://ac.nowcoder.com/acm/contest/888/B来源：牛客网题目描述Gromah and LZR have entered the second level. There is a sequence a1,a2,⋯ ,ana_1, a_2, \cdots, a_na1​,a2​,⋯,an​on the wall.There is a...

https://nanti.jisuanke.com/t/41389The value of a string s is equal to the number of different letters which appear in this string.Your task is to calculate the total value of all the palindrome su...