Alex_McAvoy的博客

【概念】1.组合从 n 个元素的集合 S 中，无序的选出 r 个元素，叫做 S 的一个 r 组合。如果两个组合中，至少有一个元素不同，它们就被认为是不同的组合。2.不可重组合数所有不同组合的个数，叫做组合数，记作：或由于每一种组合都可以扩展到 r！种排列，而总排列为 A(n,r) ，所以组合数特别的，C(n,0)=13.可重复组合数从 n 个不同的元素中，无...

Problem DescriptionMs.Fang loves painting very much. She paints GFW(Great Funny Wall) every day. Every day before painting, she produces a wonderful color of pigments by mixing water and some bags ...

Problem DescriptionComputing the exact number of ways that N things can be taken M at a time can be a great challenge when N and/or M become very large. Challenges are the stuff of contests. Theref...

Problem DescriptionIn how many ways can you choose k elements out of n elements, not taking order into account?Write a program to compute this number.InputThe input will contain one or more ...

Problem DescriptionA rook is a piece used in the game of chess which is played on a board of square grids. A rook can only move vertically or horizontally from its current position and two rooks at...

【题目描述】设S是一个具有n个元素的集合，S＝〈a1，a2，……，an〉，现将S划分成k个满足下列条件的子集合S1，S2，……，Sk且满足：1．Si≠∅2．Si∩Sj＝∅ (1≤i，j≤k，i≠j)3．S1∪S2∪S3∪…∪Sk＝S则称S1，S2，……，Sk是集合S的一个划分。它相当于把S集合中的n个元素a1，a2，……，an放入k个(0＜k≤n＜30)无标号的盒子中，使得没有...