题目传送门 /* 题意:给n块砖头,问能组成多少个楼梯,楼梯至少两层,且每层至少一块砖头,层与层之间数目不能相等! 递推DP:dp[i][j] 表示总共i块砖头,最后一列的砖头数是j块的方案数 状态转移方程:dp[i][j] += dp[i-j][k] 表示最后一列是j,那么上一个状态是少了最后一列 总共i-j块砖头,倒数第二列是k块砖头.k<j, j<=i 最后累加dp[n][i], i<n因为最少要两层 dp[0][0] = 1; 还有更简单的做法,没看懂:http://m.blog…

http://acm.timus.ru/problem.aspx?space=1&num=1017 #include <cstdio> #include <cstring> #include <algorithm> #define maxn 600 using namespace std; __int64 dp[maxn][maxn]; int main() { int n; scanf("%d",&n); memset(dp,,si…

http://acm.timus.ru/problem.aspx?space=1&num=1017 题意:有n块砖,要求按照严格递增的个数摆放成楼梯,求楼梯的摆放种类数. 思路:状态转移方程:dp[i][j]=sum(dp[i-j][k]), 0 < k < j; i 表示砖的总数,j表示最高的那层的个数. #include <stdio.h> #include <string.h> #define LL long long ; LL dp[N][N]; int…

列表: URAL 1225 Flags URAL 1009 K-based Numbers URAL 1119 Metro URAL 1146 Maximum Sum URAL 1203 Scientific Conference URAL 1353 Milliard Vasya's Function URAL 1260 Nudnik Photographer URAL 1012 K-based Numbers. Version 2 URAL 1073 Square Country URAL 1…

URAL题解一 URAL 1002 题目描述:一种记住手机号的方法就是将字母与数字对应,如图.这样就可以只记住一些单词,而不用记住数字.给出一个数字串和n个单词,用最少的单词数来代替数字串,输出对应的任一方案. solution 首先想到的应该是DP,接着就是状态转移的问题,也就是预处理出每个单词可以与哪一段的数字对应,分析时间复杂度,发现直接暴力判断是可以的,但用HASH会好一些,还可以用KMP. 时间复杂度:\(O(单词数*数字长度)或O(单词长度*数字长度)\) URAL 1010 题目描…

1017 - Exact cover 时间限制:15秒 内存限制:128兆 自定评测 5584 次提交 2975 次通过 题目描述 There is an N*M matrix with only 0s and 1s, (1 <= N,M <= 1000). An exact cover is a selection of rows such that every column has a 1 in exactly one of the selected rows. Try to find o…

题目链接 题意:求给定的字符串的最长回文子串 分析:做法是构造一个新的字符串是原字符串+反转后的原字符串(这样方便求两边回文的后缀的最长前缀),即newS = S + '$' + revS,枚举回文串中心位置,RMQ询问LCP = min (height[rank[l]+1] to height[rank[r]]),注意的是RMQ传入参数最好是后缀的位置,因为它们在树上的顺序未知,且左边还要+1. #include <cstdio> #include <algorithm> #in…

2071. Juice Cocktails Time limit: 1.0 secondMemory limit: 64 MB Once n Denchiks come to the bar and each orders a juice cocktail. It could be from 1 to 3 different juices in each cocktail. There are three juices in the bar: apple, banana and pineappl…

2073. Log Files Time limit: 1.0 secondMemory limit: 64 MB Nikolay has decided to become the best programmer in the world! Now he regularly takes part in various programming contests, attentively listens to problems analysis and upsolves problems. But…

2070. Interesting Numbers Time limit: 2.0 secondMemory limit: 64 MB Nikolay and Asya investigate integers together in their spare time. Nikolay thinks an integer is interesting if it is a prime number. However, Asya thinks an integer is interesting i…