UVALive - 3942 Remember the Word A potentiometer, or potmeter for short, is an electronic device with a variable electric resistance. It has two terminals and some kind of control mechanism (often a dial, a wheel or a slide) with which the resistance…

UVALive - 3942 Remember the Word Neal is very curious about combinatorial problems, and now here comes a problem about words. Know- ing that Ray has a photographic memory and this may not trouble him, Neal gives it to Jiejie. Since Jiejie can’t remem…

UVAlive 3942 Remember the Word 题目: Remember the Word   Time Limit: 3000MS   Memory Limit: Unknown   64bit IO Format: %lld & %llu Submit Status Description Neal is very curious about combinatorial problems, and now here comes a problem about words. Kn…

/** 题目:UVALive 3942 Remember the Word 链接:https://vjudge.net/problem/UVALive-3942 题意:给定一个字符串(长度最多3e5)和m个单词(每个单词长度最多100).单词都是不同的.该字符串可以由若干个单词组成,问最多有多少种组合方式. 思路:字典树+dp 用字典树处理好m个单词,定义dp[i]表示从i开始的字符串可以由单词组成的方式数. 那么dp[i] += dp[i+j]; j表示某个单词和字符串的[i,i+j-1]匹配…

状态是DAG,因此方案用dp统计,dp[i] = sum(dp[i+len(x)]),x是以i开头的前缀且是单词,关键在于快速判断一个前缀是不是单词,可用Trie. 每一次转移的复杂度是O(maxlen),maxlen是单词的最长长度. #include<bits/stdc++.h> using namespace std; *//4000*98+26*26+26+1 ,sigma_size = ; int ch[maxn][sigma_size]; bool vis[maxn]; int n…

题意: 给定一篇长度为L的小写字母文章, 然后给定n个字母, 问有多少种方法用这些字母组成文章. 思路: 用dp[i]来表达[i , L]的方法数, 那么dp[i] 就可以从dp[len(x) + i]转移过来, 注意dp[L+1]要初始化为1. 递推写法 #include <bits/stdc++.h> using namespace std; ; ; char in[maxN]; int n; struct Trie { ]; int val[maxN]; int sz; ; memset…

题目链接:https://icpcarchive.ecs.baylor.edu/index.php?option=com_onlinejudge&Itemid=8&page=show_problem&problem=1943 题意:一个长字符串和多个短字符串,求短字符串有多少种方式组成长字符串. 状态转移方程: dp[i] = sum(d[i + len(x)])  (x是s[i...L]的前缀) 对于每个i,如果直接暴力寻找s[i...L]的前缀,复杂度为O(nm) (n为短字符…

题意:告诉你一个母串和子串,能用多少种不同的方案组合出母串. 思路:字典树(显然)+DP DP: dp[i]+=dp[j+1]  i<=j<=m-1,且i到j的字符串能在字典树中找到.也就等价dp[i]=1*dp[j+1] #include <cstdio> #include <cstring> #include <cmath> #include <cstdlib> #include <iostream> #include <a…

题意:给出一个由S个不同单词组成的字典和一个长字符串.把这个字符串分解成若干个单词的连接(单词可以重复 使用),有多少种方法? Sample Input abcd 4 a b cd ab Sample Output Case 1: 2 思路:利用字典树上的dp,dp[i]表示从i到末尾有多少种方案,大白书字典树的例题,虽然是例题还是看了一会儿orz, 我太弱了,注意ch数组要开成最大节点数*26的大小,表示每个节点连的字母是什么,初始节点为0,val也要开 成最大节点数的大小,表示该节点是否为单…

3942 - Remember the Word Neal is very curious about combinatorial problems, and now here comes a problem about words. Knowing that Ray has a photographic memory and this may not trouble him, Neal gives it to Jiejie. Since Jiejie can't remember number…