xuanweiace的博客

题目大意：给定一棵树，从1开始，按DFS的方式访问这棵树每次从父亲节点随机访问儿子，问每个节点被访问到的时间的期望输入：第一行一个数n，代表n个节点。第二行n-1个数p2,p3,p4,p5...,pn-1，其中pi代表i号节点的父节点编号，1号节点一定是根节点。ExamplesInput71 2 1 1 4 4Output1.0 4.0 5.0 3.5 4....

题干：Avin is studying how to synthesize data. Given an integer n, he constructs an interval using the following method: he first generates a integer r between 1 and n (both inclusive) uniform-randomly...

题干：Recently Kumiko learns to use containers in C++ standard template library.She likes to use thestd::vectorvery much. It is very convenient for her to do operations like an ordinary array. Howe...

题干：There is a very simple and interesting one-person game. You have 3 dice, namelyDie1,Die2andDie3.Die1hasK1faces.Die2hasK2faces.Die3hasK3faces. All the dice are fair dice, so the pr...

题干：Ivan is fond of collecting. Unlike other people who collect post stamps, coins or other material stuff, he collects software bugs. When Ivan gets a new program, he classifies all possible bugs in...

题干：Here’s a jolly and simple game: line up a row ofNidentical coins, all with the heads facing down onto the table and the tails upwards, and for exactlyKtimes take one of the coins, toss it int...

题干：随着新版百度空间的下线，Blog宠物绿豆蛙完成了它的使命，去寻找它新的归宿。给出一个有向无环的连通图，起点为1终点为N，每条边都有一个长度。绿豆蛙从起点出发，走向终点。到达每一个顶点时，如果有K条离开该点的道路，绿豆蛙可以选择任意一条道路离开该点，并且走向每条路的概率为 1/K 。现在绿豆蛙想知道，从起点走到终点的所经过的路径总长度期望是多少？Input第一行: 两个整数...

题干：Momiji has got a rooted tree, consisting ofnnodes. The tree nodes are numbered by integers from1ton. The root has number1. Momiji decided to play a game on this tree.The game consists of ...

题干：Sometimes some mathematical results are hard to believe. One of the common problems is the birthday paradox. Suppose you are in a party where there are23people including you. What is the probab...

题干：osu 是一款群众喜闻乐见的休闲软件。我们可以把osu的规则简化与改编成以下的样子:一共有n次操作，每次操作只有成功与失败之分，成功对应1，失败对应0，n次操作对应为1个长度为n的01串。在这个串中连续的 X个1可以贡献X^3 的分数，这x个1不能被其他连续的1所包含（也就是极长的一串1，具体见样例解释）现在给出n，以及每个操作的成功率，请你输出期望分数，输出四舍五入后...

题干：某一天WJMZBMR在打osu~~~但是他太弱逼了，有些地方完全靠运气:(我们来简化一下这个游戏的规则有n次点击要做，成功了就是o，失败了就是x，分数是按comb计算的，连续a个comb就有a*a分，comb就是极大的连续o。比如ooxxxxooooxxx，分数就是2*2+4*4=4+16=20。Sevenkplus闲的慌就看他打了一盘，有些地方跟运气无关要么是o要么是x，有些地...

题干：Ilya got tired of sports programming, left university and got a job in the subway. He was given the task to determine the escalator load factor.Let's assume thatnpeople stand in the queue for...

题干：As Harry Potter series is over, Harry has no job. Since he wants to make quick money, (he wants everything quick!) so he decided to rob banks. He wants to make a calculated risk, and grab as much...

题干：Rimi learned a new thing about integers, which is - any positive integer greater than1can be divided by its divisors. So, he is now playing with this property. He selects a numberN. And he cal...

题干：You are in a cave, a long cave! The cave can be represented by a1 x Ngrid. Each cell of the cave can contain any amount of gold.Initially you are in position1. Now each turn you throw a perf...

题干：You are in a maze; seeingndoors in front of you in beginning. You can choose any door you like. The probability for choosing a door is equal for all doors.If you choose theithdoor, it can e...