我们查看更一般的情况,设人数为m 则n < m * 2无解 然后n为奇数的情况: 我们把一个人和一个空格打包,于是剩下m个"人"和n - m个空格,随便排列这些"人",然后把空格插入 本质不同的"人"的圆周排列有(m - 1)!个,对于每个排列,有m个位置插入n - m个空格,有C(n - m - 1, m - 1)中方法,然后对于一个排列,圆周排列有n个 ans = C(n - m - 1, m - 1) * (m - 1)! * n 最…

几年前,一篇表述“10个Scala函数式单行代码”的文章非常受欢迎,并且随后立马出现了其他的语言版本,例如Haskell版本,Ruby版本,Groovy版本,Clojure版本,Python版本,C#版本,F#版本,CoffeeScript版本等. 我们不知道有多少人真的对这些单行代码印象深刻,但我认为,这能激励大家去了解更多有关于函数式编程的内容. 1 数组中的每个元素乘以2 特别简单,尤其是使用map解决的话. 1 (1...1024).map{$0 * 2} 2 数组中的元素求和 虽然这里…

小需求是当你在第一个下拉框选择了国家时,会自动更新第二个省份的下拉框,效果如下 两个下拉选择Html如下: <select id="country_select"> <option> All Countries</option> <option> Afghanistan</option> <option> Albania</option> <option> Algeria</optio…

Prince and Princess Time Limit: 6000/3000 MS (Java/Others)    Memory Limit: 65535/32768 K (Java/Others)Total Submission(s): 1267    Accepted Submission(s): 358 Problem Description There are n princes and m princesses. Princess can marry any prince. B…

#瓦登尔湖词频统计: import string path = 'D:/python3/Walden.txt' with open(path,'r',encoding= 'utf-8') as text: words = [raw_word.strip(string.punctuation).lower() for raw_word in text.read().split()] words_index = set(words) counts_dict = {index:words.count(…

Somewhere in the great stone maze(迷宫:迷惑) of Winterfell, a wolf howled. The sound hung over the castle like a flag of mourning(哀痛:服丧). Tyrion Lannister looked up from his books and shivered, though the library was snug(舒适的:温暖的) and warm. Something abo…

Arya’s stitches were crooked again. She frowned down at them with dismay and glanced over to where her sister Sansa sat among the other girls. Sansa’s needlework was exquisite. Everyone said so. “Sansa’s work is as pretty as she is,” Septa Mordane to…

Of all the rooms in Winterfell’s Great Keep, Catelyn’s bedchambers(['bedtʃeɪmbə]卧室,寝室) were the hottest. She seldom had to light a fire. The castle had been built over natural hot springs, and the scalding(['skɔːldɪŋ]滚烫的:尖刻的) waters rushed through it…

There were times—not many, but a few—when Jon Snow was glad he was a bastard. As he filled his wine cup once more from a passing flagon(['flægən]酒壶), it struck him that this might be one of them. He settled back in his place on the bench among the yo…

Her brother held the gown up for her inspection. “This is beauty. Touch it. Go on. Caress(爱抚,抚抱) the fabric.” Dany touched it. The cloth was so smooth that it seemed to run through her fingers like water. She could not remember ever wearing anything…