AT3576 Popping Balls 好题!一种以前没怎么见过的思路! %%ywy 以什么方式,什么位置统计本质不同的方案,才能不重不漏是处理所有计数问题的主心骨. 本题难以容斥.难以DP. 所以就尝试挖掘性质,考虑过程! 首先,红色什么时候都可以选,因为可以选择1 不妨给t定一个位置,先充分利用t,再用s,(如果s先用上了,那么t肯定就没意义了) 考虑每个方案是怎样构造出来的,归到合适的t的位置统计. 不妨直接按照“先拿了x个红的,再拿一个蓝的”为标准统计! 为了能涵盖所有之后的决策,让t…

题目:https://code-festival-2017-qualb.contest.atcoder.jp/tasks/code_festival_2017_qualb_e 题解:https://www.cnblogs.com/Miracevin/p/10963431.html #include<cstdio> #include<cstring> #include<algorithm> #define ll long long using namespace std;…

题目链接 题意 \(A+B\)个球排成一行,左边\(A\)个为红球,右边\(B\)个为蓝球. 最开始可以选择两个数\(s,t\),每次操作可以取左起第\(1\)或\(s\)或\(t\)个球.问有多少种不同的取球序列. Sample Sample Input 1 3 3 Sample Output 1 20 Explanation There are 20 ways to give 3 red balls and 3 blue balls. It turns out that all of the…

蒟蒻__stdcall终于更新博客辣~ 一下午+一晚上=一道计数题QAQ 为什么计数题都这么玄学啊QAQ Prelude 题目链接:这里是传送门=￣ω￣= 下面我将分几个步骤讲一下这个题的做法,大家不必一次看完,可以一点一点地推进思路,希望对锻炼大家的思维能力有帮助o(￣▽￣)ブ. Step 1 首先要看出来这是一个计数题对吧... 计数题有很多做法,对于这个题,我们考虑合理枚举,即不重复不遗漏地枚举所有情况,然后乘上一个组合数,并通过前缀和优化来降低复杂度. Step 2 枚举什么东西呢? 我…

传送门 神仙计数! 我的计数真的好差啊= = 不过这个题真的神仙 看了题解把整个过程在草稿纸上重写了一遍才想明白= =(一张草稿纸就没有了!!!) 计数的关键就是在于 枚举的有效性和独立性[不能重复计数] 然后我们就来思考一下这个题 1. 确定t 我们重定义t为第一个取出的蓝球的位置 那么t的选择区间是[1,a+1] 分别对应[a+1,1]的时候取出 枚举区间:[1,a+1] 2.枚举i 取走前面的 a+1-t个 红球 和 在位置t的 1个 蓝球(根据第一步的定义) 这个时候总共取出了 a-t+…

CF79D Password: 差分.两点取反,本质是匹配!最短路+状压DP 取反是套路,匹配是发现可以把操作进行目的化和阶段化,从而第二次转化问题. 且匹配不会影响别的位置答案 sequence 计算最长极长段小于等于j的方案数 突破口是i,k总共对数nlogn级别,干掉j用组合意义大力推导 CF1062F Upgrading Cities DAG考虑topo,关键性质:topo序队列中点两两不可达.只在队列长度<=2时候才关心. CF1060F Shrinking Tree 考虑x是不是rt…

按照顺序来. Median Sum 大意: 给你一个集合,求其所有非空子集的权值的中位数. 某集合的权值即为其元素之和. 1 <= n <= 2000 解: 集合配对,每个集合都配对它的补集. 最大的那个没有配对,所以求(原集合的权值 + 1) >> 1,不小于这个的第一个即为所求. 用bitset实现可行性背包. #include <cstdio> #include <bitset> ; std::bitset<N * N> bt; int a…

最近不知道为啥被安利了饥荒,但是不能再玩物丧志了,不能颓了 饥荒真好玩 A - XXFESTIVAL CCFESTIVAL #include <bits/stdc++.h> #define fi first #define se second #define pii pair<int,int> #define mp make_pair #define pb push_back #define space putchar(' ') #define enter putchar('\n'…

失踪人口回归.撒花\^o^/ 说来真是惭愧,NOI之后就没怎么刷过题,就写了几道集训队作业题,打了几场比赛还烂的不行,atcoder至今是蓝名=.= 以后还是多更一些博客吧,我可不想清华集训的时候就退役 A - XXFESTIVAL 题意:输入XXFESTIVAL,输出XX... #include<bits/stdc++.h> using namespace std; char s[1005]; int main() { scanf("%s",s); int n=strle…

C. Kyoya and Colored Balls Time Limit: 2000ms Memory Limit: 262144KB 64-bit integer IO format: %I64d      Java class name: (Any) Submit Status Kyoya Ootori has a bag with n colored balls that are colored with k different colors. The colors are labele…

今天讨论的是称球问题. No.3 13 balls problem You are given 13 balls. The odd ball may be either heavier or lighter. Find out the odd ball in 3 weightings. 分析与解答: 看到这道题,就想起来高中时候数学老师的一句话:“真正难的题不是那些很长的题,而是那些就几句话的题!!!”现在想想真是良训啊.又想到很多老师的话,感觉到失去方显弥足珍贵的名言,不禁唏嘘啊…… 有人认为…

C16H:Magical Balls 总时间限制:  1000ms 内存限制:  262144kB 描述 Wenwen has a magical ball. When put on an infinite plane, it will keep duplicating itself forever. Initially, Wenwen puts the ball on the location (x0, y0) of the plane. Then the ball starts to dup…

http://acm.hdu.edu.cn/showproblem.php?pid=4710 Balls Rearrangement Time Limit: 6000/3000 MS (Java/Others)    Memory Limit: 32768/32768 K (Java/Others) Total Submission(s): 735    Accepted Submission(s): 305 Problem Description Bob has N balls and A b…

Dragon Balls Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 32768/32768 K (Java/Others)Total Submission(s): 2909    Accepted Submission(s): 1125 Problem Description Five hundred years later, the number of dragon balls will increase unexpecte…

Labeling Balls Time Limit: 1000MS Memory Limit: 65536K Total Submissions: 9641 Accepted: 2636 Description Windy has N balls of distinct weights from 1 unit to N units. Now he tries to label them with 1 to N in such a way that: No two balls share the…

Labeling Balls Time Limit: 1000MS Memory Limit: 65536K Total Submissions: 11893 Accepted: 3408 Description Windy has N balls of distinct weights from 1 unit to N units. Now he tries to label them with 1 to N in such a way that: No two balls share the…

 Balls and Boxes(盒子与球) Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 65536/65536 K (Java/Others) Description 题目描述 Mr. Chopsticks is interested in random phenomena, and he conducts an experiment to study randomness. In the experiment, he thr…

C. Balls and Boxes time limit per test 1 second memory limit per test 256 megabytes input standard input output standard output Little Vasya had n boxes with balls in the room. The boxes stood in a row and were numbered with numbers from 1 to n from…

Dragon Balls Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 32768/32768 K (Java/Others)Total Submission(s): 3363    Accepted Submission(s): 1304 Problem Description Five hundred years later, the number of dragon balls will increase unexpecte…

Kyoya Ootori has a bag with n colored balls that are colored with k different colors. The colors are labeled from 1 to k. Balls of the same color are indistinguishable. He draws balls from the bag one by one until the bag is empty. He noticed that he…

C. Kyoya and Colored Balls Time Limit: 20 Sec Memory Limit: 256 MB 题目连接 http://codeforces.com/contest/554/problem/C Description Kyoya Ootori has a bag with n colored balls that are colored with k different colors. The colors are labeled from 1 to k.…

Balls and Boxes 题目链接: http://acm.hdu.edu.cn/showproblem.php?pid=5810 Description Mr. Chopsticks is interested in random phenomena, and he conducts an experiment to study randomness. In the experiment, he throws n balls into m boxes in such a manner t…

A. Bear and Three Balls time limit per test 2 seconds memory limit per test 256 megabytes input standard input output standard output Limak is a little polar bear. He has n balls, the i-th ball has size ti. Limak wants to give one ball to each of his…

balls Time Limit: 20 Sec Memory Limit: 256 MB 题目连接 http://acm.hdu.edu.cn/showproblem.php?pid=5570 Description There are n balls with m colors. The possibility of that the color of the i-th ball is color j is ai,jai,1+ai,2+...+ai,m. If the number of b…

Dragon Balls Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 32768/32768 K (Java/Others) Total Submission(s): 5340    Accepted Submission(s): 2014 Problem Description Five hundred years later, the number of dragon balls will increase unexpect…

Labeling Balls DescriptionWindy has N balls of distinct weights from 1 unit to N units. Now he tries to label them with 1 to N in such a way that:No two balls share the same label.The labeling satisfies several constrains like "The ball labeled with…

作者:jostree 转载请注明出处 http://www.cnblogs.com/jostree/p/4098409.html 题目链接:poj 3783 Balls 动态规划 100层楼投鸡蛋问题 使用动态规划算法,使用$dp[i][j]$表示对于i层楼并拥有$j$个鸡蛋时能够判断鸡蛋质量需要的最少次数.假如我们在第$k$层扔下一个鸡蛋,则有两种情况,如果鸡蛋没有损坏则问题相当于我们对于$i-k$层楼拥有$j$个鸡蛋所需的最少的次数.如果鸡蛋损坏了,则问题相当于对于k层楼拥有$j-1$个鸡蛋…

Labeling Balls Time Limit: 1000MS   Memory Limit: 65536K Total Submissions: 12246   Accepted: 3508 Description Windy has N balls of distinct weights from 1 unit to N units. Now he tries to label them with 1 to N in such a way that: No two balls share…

Dragon Balls Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 32768/32768 K (Java/Others)Total Submission(s): 4384    Accepted Submission(s): 1673 Problem Description Five hundred years later, the number of dragon balls will increase unexpecte…

题意: 有k种颜色,每种颜色对应a[i]个球,球的总数不超过1000 要求第i种颜色的最后一个球,其后面接着的必须是第i+1种颜色的球 问一共有多少种排法 Sample test(s) input output input output Note In the first sample, we have 2 balls of color 1, 2 balls of color 2, and 1 ball of color 3. The three ways for Kyoya are: 思路:…