Problem B. Harvest of Apples Time Limit: / MS (Java/Others) Memory Limit: / K (Java/Others) Total Submission(s): Accepted Submission(s): Problem Description There are n apples on a tree, numbered to n. Count the number of ways to pick at most m apple…
题目连接:Harvest of Apples 题意:给出一个n和m,求C(0,n)+C(1,n)+.....+C(m,n).(样例组数为1e5) 题解:首先先把阶乘和逆元预处理出来,这样就可O(1)将C(m,n)求出来了.但这样还是会超时,所以接下来要分块,每隔500个处理出C(1~m,n)的结果.然后还要知道一个性质 C(a,b) = ∑C(t1,x)*C(t2,y) (x+y<=b),这样我们就可以将给出的m和n分为两个组,其中一个组中元素的个数为500的倍数.然后我们对于另一个组枚举可能…
任意门:http://acm.hdu.edu.cn/showproblem.php?pid=6333 Problem B. Harvest of Apples Time Limit: 4000/2000 MS (Java/Others) Memory Limit: 262144/262144 K (Java/Others)Total Submission(s): 4043 Accepted Submission(s): 1560 Problem Description There a…
2018 Multi-University Training Contest 4 6333.Problem B. Harvest of Apples 题意很好懂,就是组合数求和. 官方题解: 我来叨叨一些东西. 这题肯定不能一个一个遍历求和,这样就上天了... 解释一下官方题解的意思. 为什么 sum(n,m)=2*sum(n-1,m)-c(n-1,m). 因为c(n,m)=c(n-1,m)+c(n-1,m-1),至于为什么成立,不懂的百度一下组合数和杨辉三角吧... sum(n,m)=c(n,…
问题 B: Harvest of Apples 时间限制: 1 Sec 内存限制: 128 MB提交: 18 解决: 11[提交] [状态] [讨论版] [命题人:admin] 题目描述 There are n apples on a tree, numbered from 1 to n.Count the number of ways to pick at most m apples. 输入 The first line of the input contains an integer T…
Problem B. Harvest of Apples Time Limit: 4000/2000 MS (Java/Others) Memory Limit: 262144/262144 K (Java/Others)Total Submission(s): 3088 Accepted Submission(s): 1201 Problem Description There are n apples on a tree, numbered from 1 to n.Count t…
Problem Description There are n apples on a tree, numbered from 1 to n.Count the number of ways to pick at most m apples. Input The first line of the input contains an integer T (1≤T≤105) denoting the number of test cases.Each test case consists of…