题目:http://acm.hdu.edu.cn/showproblem.php?pid=1133 题目的意思是,m个人只有50元钱,n个人只有100元整钱,票价50元/人.现在售票厅没钱,只有50元钱的人可以不用找钱顺利买票,而拿着100元整钱的人只有在前面有50元的情况下才能买票,因为只有这样,才能找零50元.所有的人能否买票和排队的方式有一定关系,问使得所有的人能够顺利买票的排队方式有多少种? 上述问题可以抽象为下面的数学模型,数学模型及求解过程如下图: 本题中每个人是不一样的,所以本题的…

题目链接:https://vjudge.net/problem/HDU-1133 Buy the Ticket Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 65536/32768 K (Java/Others)Total Submission(s): 7427    Accepted Submission(s): 3105 Problem Description The "Harry Potter and the Goblet…

设50元的人为+1 100元的人为-1 满足前随意k个人的和大于等于0 卡特兰数 C(n+m, m)-C(n+m, m+1)*n!*m! import java.math.*; import java.util.*; public class Main { /** * @param args */ public static void main(String[] args) { Scanner sc = new Scanner(System.in); int cas = 1; while(tru…

Problem Description The "Harry Potter and the Goblet of Fire" will be on show in the next few days. As a crazy fan of Harry Potter, you will go to the cinema and have the first sight, won't you? Suppose the cinema only has one ticket-office and…

Train Problem II Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 65536/32768 K (Java/Others) Total Submission(s): 7539    Accepted Submission(s): 4062 Problem Description As we all know the Train Problem I, the boss of the Ignatius Train Stat…

题目代号:HDU 1134 题目链接:http://acm.hdu.edu.cn/showproblem.php?pid=1134 Game of Connections Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 65536/32768 K (Java/Others)Total Submission(s): 4668    Accepted Submission(s): 2729 Problem Description Thi…

题目链接 分析:打表以后就能发现时卡特兰数, 但是有除法取余. f[i] = f[i-1]*(4*i - 2)/(i+1); 看了一下网上的题解,照着题解写了下面的代码,不过还是不明白,为什么用扩展gcd, 不是用逆元吗.. 网上还有别人的解释,没看懂,贴一下: (a / b) % m = ( a % (m*b)) / b 笔者注:鉴于ACM题目特别喜欢M=1000000007,为质数: 当gcd(b,m) = 1, 有性质: (a/b)%m = (a*b^-1)%m, 其中b^-1是b模m的逆…

题目链接:http://acm.hdu.edu.cn/showproblem.php?pid=1130 卡特兰数:https://blog.csdn.net/qq_33266889/article/details/53409553 参考文章:https://blog.csdn.net/sunshine_YG/article/details/47685737 #include<iostream> #include<cstdio> #include<cstring> usi…

How Many Trees? Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 65536/32768 K (Java/Others)Total Submission(s): 3382    Accepted Submission(s): 1960 Problem Description A binary search tree is a binary tree with root k such that any node v re…

卡特兰数: Catalan数 原理: 令h(1)＝1,h(0)=1,catalan数满足递归式: h(n)= h(1)*h(n-1) + h(2)*h(n-2) + ... + h(n-1)h(1) (其中n>=2) 另类递归式: h(n)=((4*n-2)/(n+1))*h(n-1); 该递推关系的解为: h(n+1)=C(2n,n)/(n+1) (n=1,2,3,...) 最典型的四类应用:(实质上却都一样,无非是递归等式的应用,就看你能不能分解问题写出递归式了) 1.括号化问题. 矩阵链乘…