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…

题意:n<20个箱子,每个里面有fi朵颜色相同的花,不同箱子里的花颜色不同,要求取出s朵花,问方案数 题解:假设不考虑箱子的数量限制,隔板法可得方案数是c(s+n-1,n-1),当某个箱子里的数量超过fi时,方案数是c(s-f[i]-1+n-1,n-1),容斥原理求,状压枚举哪几个箱子超过了f[i],答案就是超过0个-超过1个+超过2个... 由于c(n,m)的m很小,直接暴力求解 //#pragma GCC optimize(2) //#pragma GCC optimize(3) //#pr…

Codeforces Round #258 (Div. 2)[ABCD] ACM 题目地址:Codeforces Round #258 (Div. 2) A - Game With Sticks 题意:  Akshat and Malvika两人玩一个游戏,横竖n,m根木棒排成#型,每次取走一个交点,交点相关的横竖两条木棒要去掉,Akshat先手,给出n,m问谁赢. 分析:  水题,非常明显无论拿掉哪个点剩下的都是(n-1,m-1),最后状态是(0,x)或(x,0),也就是拿了min(n,m)-…

A. Game With Sticks (451A) 水题一道,事实上无论你选取哪一个交叉点,结果都是行数列数都减一,那如今就是谁先减到行.列有一个为0,那么谁就赢了.因为Akshat先选,因此假设行列中最小的一个为奇数,那么Akshat赢,否则Malvika赢. 代码: #include <iostream> #include <cstdio> #include <cstring> #include <algorithm> using namespace…

题目链接: http://codeforces.com/problemset/problem/451/E E. Devu and Flowers time limit per test4 secondsmemory limit per test256 megabytes 问题描述 Devu wants to decorate his garden with flowers. He has purchased n boxes, where the i-th box contains fi flow…

A - Game With Sticks 题目的意思: n个水平条,m个竖直条,组成网格,每次删除交点所在的行和列,两个人轮流删除,直到最后没有交点为止,最后不能再删除的人将输掉 解题思路: 每次删除交点所在的行和列,则剩下n-1行和m-1列,直到行或列被删完为止,最多删除的次数为min(n,m),删除min(n,m)后剩余的都是行或者列(注意行与行,列与列之间不可能有交点).只需要判断min(n,m)的奇偶性. #include <iostream> #include <vector&…

http://blog.csdn.net/rowanhaoa/article/details/38116713 A:Game With Sticks 水题.. . 每次操作,都会拿走一个横行,一个竖行. 所以一共会操作min(横行,竖行)次. #include<stdio.h> #include<iostream> #include<stdlib.h> #include<string.h> #include<algorithm> #include…

题目链接:http://codeforces.com/contest/451/problem/B 思路:首先找下降段的个数,假设下降段是大于等于2的,那么就直接输出no,假设下降段的个数为1,那么就把下降段的起始位置和结束位置记录下来然后进行推断,在进行推断时,有几种特殊情况:(s表示起始位置,e表示结束位置) 1.当e==n&&s!=1时,满足a[n]>a[s-1]输出yes: 2当s==1&&==n时,满足a[1]<a[e+1] 输出yes: 3当s==1&…

D. Count Good Substrings 题目连接: http://codeforces.com/contest/451/problem/D Description We call a string good, if after merging all the consecutive equal characters, the resulting string is palindrome. For example, "aabba" is good, because after…

C. Predict Outcome of the Game 题目连接: http://codeforces.com/contest/451/problem/C Description There are n games in a football tournament. Three teams are participating in it. Currently k games had already been played. You are an avid football fan, but…