Yaroslav has n points that lie on the $Ox$ axis. The coordinate of the first point is $x_1$, the coordinate of the second point is $x_2$, ..., the coordinate of the n-th point is — $x_n$. Now Yaroslav wants to execute $m$ queries, each of them is of one of the two following types:
In mathematical terms, the sequence $F_n$ of Fibonacci numbers is defined by the recurrence relation
$$F_1 = 1; F_2 = 1; F_n = F_{n - 1} + F_{n - 2} (n > 2)$$
DZY loves Fibonacci numbers very much. Today DZY gives you an array consisting of n integers: $a_1, a_2, \dots, a_n$. Moreover, there are $m$ queries, each query has one of the two types:
快看看 CCF 是怎么把初赛完成脑筋急转弯竞赛的……
孙某和张某是考古学家老李的学生。有一天，老李拿了一件古物来考验两人，两人都无法验证出来这件古物试谁的。老李告诉了孙某拥有者的姓，告诉张某拥有者的名，并且在纸条上写下以下几个人的人名，问他们知道谁才是拥有者？
纸条上的名字有：沈万三、岳飞、岳云、张飞、张良、张鹏、赵括、赵云、赵鹏、沈括。
- 孙某说：如果我不知道的话，张某肯定也不知道。
- 张某说：刚才我不知道，听孙某一说，我现在知道了。
- 孙某说：哦，那我也知道了。
请问：那件古物是谁的？
Link: LightOJ 1873 DNA Sequence
You are given a list of strings over the alphabet A (for adenine), C (cytosine), G (guanine), and T (thymine), and your task is to find the shortest string (which is typically not listed) that contains all given strings as substrings. If there are several such strings of shortest length, find the smallest in alphabetical/lexicographical order.
Time Limit: 4 second(s)
Memory Limit: 32 MB
$$ \begin{bmatrix} x_{11} & x_{12} & x_{13} \\ x_{21} & x_{22} & x_{23} \\ x_{31} & x_{32} & x_{33} \end{bmatrix} $$
每增加一个维度，世界便会增加无限的美感。
简单来说，数位 DP 大概就是把一个数字拆开按位进行 DP 的一种思想。
The counter-terrorists found a time bomb in the dust. But this time the terrorists improve on the time bomb. The number sequence of the time bomb counts from 1 to N. If the current number sequence includes the sub-sequence "49", the power of the blast would add one point.
Now the counter-terrorist knows the number N. They want to know the final points of the power. Can you help them?
据说今年所有学校都没有推荐名额？？？
很多题目的贪心想法都是一个简单粗暴的贪心加上可“反悔”的操作。这样可以确保答案的正确性。
You're Zhu Rengong, a formidable hero. After a number of challenging missions, you are finally facing the final Boss – a black dragon called Heilong. Due to his overwhelming power, you have to plan your actions carefully.