Discription Devu wants to decorate his garden with flowers. He has purchased n boxes, where the i-th box contains fi flowers. All flowers in a single box are of the same color (hence they are indistinguishable). Also, no two boxes have flowers of the…
传送门 解题思路: 假如只有 s 束花束并且不考虑 f ,那么根据隔板法的可重复的情况时,这里的答案就是 假如说只有一个 f 受到限制,其不合法时一定是取了超过 f 的花束 那么根据组合数,我们仍然可以算出其不合法的解共有: 最后,由于根据容斥,减两遍的东西要加回来,那么含有偶数个 f 的项为正,奇数个时为负. 答案就是: 搜索答案,使用Lucas定理,计算组合数上下约去. 代码: #include<cstdio> #include<cstring> #include<alg…
E. Devu and Flowers 题目连接: http://codeforces.com/contest/451/problem/E Description Devu wants to decorate his garden with flowers. He has purchased n boxes, where the i-th box contains fi flowers. All flowers in a single box are of the same color (hen…
Codeforces Round #258 (Div. 2) Devu and Flowers E. Devu and Flowers time limit per test 4 seconds memory limit per test 256 megabytes input standard input output standard output Devu wants to decorate his garden with flowers. He has purchased n boxes…
E. Devu and Flowers time limit per test 4 seconds memory limit per test 256 megabytes input standard input output standard output Devu wants to decorate his garden with flowers. He has purchased n boxes, where the i-th box contains fi flowers. All fl…
