Code DescriptionTransmitting and memorizing information is a task that requires different coding systems for the best use of the available space. A well known system is that one where a number is associated to a character sequence. It is considered t…

poj1850 Code 题意:输出若干个给定的字符串($length<=10$)在字典序中的位置,字符串中的字母必须严格递增. 读取到非法字符串时,输出“0”,终止程序.(poj1496:继续读取) 我们分成2种情况讨论字典序小于给定字符串的字符串个数 1.长度比给定字符串小 其实长度为$i$的字符串的个数就是$C(26,i)$ 因为我们随机选取$i$个字符后,从小到大依次取出,是可以保证字符串是有序的. 2.长度等于给定字符串 我们枚举每一位,计算从该位开始小于给定字符串的个数,同样可以用组…

题意: * 按照字典序的顺序从小写字母 a 开始按顺序给出序列 (序列中都为升序字符串)* a - 1* b - 2* ...* z - 26* ab - 27* ...* az - 51* bc - 52* ...* vwxyz - 83681* 输入字符串由小写字母 a-z 组成字符串为升序,根据字符串输出在字典里的序列号为多少. 很容易地我们可以想到,设输入的字符串长度为len,我们可以用组合数求出所有小于len长度的字符串数量,(感觉这一步很好理解,反而许多题解给出了详细的证明?). 然…

Code Time Limit: 1000MS Memory Limit: 30000K Total Submissions: 8766 Accepted: 4168 Description Transmitting and memorizing information is a task that requires different coding systems for the best use of the available space. A well known system is t…

Code Time Limit: 1000MS   Memory Limit: 30000K Total Submissions: 10059   Accepted: 4816 Description Transmitting and memorizing information is a task that requires different coding systems for the best use of the available space. A well known system…

题目大意:字符的字典序依次递增才是合法的字符串,将字符串依次标号如:a-1 b-2 ... z-26 ab-27 bc-52. 为什么题解都是组合数学的...我觉得数位dp很好写啊(逃 f[pos][pre]前pos位,前一位是pre有几个满足条件的字符串,其实等同于这个字符串的序号是多少 好像数位dp的博客真没什么东西好写的... #include<iostream> #include<cstring> #include<cstdlib> #include<cs…

Code Time Limit: 1000MS   Memory Limit: 30000K Total Submissions: 8710   Accepted: 4141 Description Transmitting and memorizing information is a task that requires different coding systems for the best use of the available space. A well known system…

题目问一个合法字符串的字典序是第几个,合法的字符串是指里面的字符严格递增. 先判断合不合法,然后用类似康托展开的过程去求.大概过程就是用组合数算出某长度某前缀有几个,累加起来. 真难一遍写对.. #include<cstdio> #include<cstring> using namespace std; bool islegal(char *s){ ; s[i]; ++i){ ]) ; } ; } ][]; int main(){ ; i<; ++i) C[i][]=; ;…

题目:http://poj.org/problem?id=1850 题意:按给定的规则给字母编号. 一个很简单的题目,但是却做了好久.................................. #include<iostream> #include<cstdio> #include<cstring> using namespace std; ][]; void init()//用杨辉三角的方法求组合数,C(n,m) { int i,j; ; i<=; i+…

杭电ACM分类: 1001 整数求和 水题1002 C语言实验题——两个数比较 水题1003 1.2.3.4.5... 简单题1004 渊子赛马 排序+贪心的方法归并1005 Hero In Maze 广度搜索1006 Redraiment猜想 数论:容斥定理1007 童年生活二三事 递推题1008 University 简单hash1009 目标柏林 简单模拟题1010 Rails 模拟题(堆栈)1011 Box of Bricks 简单题1012 IMMEDIATE DECODABILITY…