Description 有一个 \(n\times n\) 的矩阵,矩阵内有 \(2n\) 个球.对于 \(i \in [1,n]\) ,\((0,i) (i,0)\) 的位置各有一个启动后往右走/往上走的机器人,机器人撞到球会和球一起消失.问启动机器人顺序的方案数,满足所有球最后都消失. \(n \le 10^{5}\) Solution 先建图,对于平面上的一个 \((x, y)\) 位置的球,把机器人看做点,球看做边,连一条 \(x\) 到 \(y + n\) ,权值为 \(x + y\)…

题面 [传送门](https://arc083.contest.atcoder.jp/tasks/arc083_d) 思路 这是一道真正的好题 第一步:转化模型 行列支配类的问题,常见做法就是把行和列变成二分图中的点,把矩阵内元素作为边,转化为图论问题 本题中,我们把第$(i,j)$格子中的球,变成连接$i$行和$j$列的无向边即可 容易发现,对于不同的联通块之间,子问题互相没有影响,因此可以对于每个块分别处理 第二步:联通块性质 观察可得,若任何一个联通块的点数和边数不相等,那么题目无解 若满…

传送门 题目大意 给定$N$,在$(1,0),(2,0)......(N,0)$和$(0,1),(0,2)...(0,N)$上都有$1$个机器人,同时给定$2N$个坐标$(x,y),x,y\in[1,N]$上有障碍,你每次可以选择一个没有被选过的机器人$K$,若$X_K=0$,则它会沿着$y$轴正方向移动直到遇到遇到障碍或移出边界$[0,N]$,若它遇到障碍,则它会和障碍一同消失. 求选择$2N$个机器人的$(2N!)$中顺序中,有多少种会使得所有障碍消失. 题解 神仙题 考虑把每一行和每一列看…

[链接]h在这里写链接 [题意] 看懂题目之后就会发现是道大水题. [题解] 在这里写题解 [错的次数] 0 [反思] 在这了写反思 [代码] #include <bits/stdc++.h> using namespace std; int n,k,ans; int main(){ //freopen("F:\\rush.txt","r",stdin); ios::sync_with_stdio(0),cin.tie(0); cin >>…

Problem ARC083F 题意概要:给定 \(2n\) 个二维平面上的球,坐标分别为 \((x_i,y_i)\),并给出 \(n\) 个 \(A\)类 机器人 和 \(n\) 个 \(B\)类 机器人,其中: \(A\)类 加5分 机器人分布在横坐标上,坐标依次为 \((1,0),(2,0),\cdots ,(n,0)\),触发第 \(i\) 个机器人,它会将位处第 \(i\) 列的最下头的球拿走(即横坐标为 \(i\) 且纵坐标最小的球) \(B\)类 不加分 机器人分布在横坐标上,坐标…

考虑一个构造,对于坐标$(x,y)$,连一条$x$到$y$的边(注意:横坐标和纵坐标即使权值相同也是不同的点),之后每一个连通块独立,考虑一个连通块内部: 每一个点意味着一次删除操作,每一个边意味着一个坐标,由于每一次操作最多删除一个点,因此首先点数要大于等于边数,同时总边数=总点数=$2n$,因此每一个连通块都是基环树 考虑叶子,其必然要删除一个点,只能是与其相连的边,重复此过程,对于不在环上的点或边都可以确定删除的配对关系,对于环上的点枚举两种方向也可以确定 接下来,就是要对于一组给定的配对…

C - Sugar Water 计算一下可以达到水是多少,可以到达的糖是多少 枚举水,然后加最多能加的糖,是\(min(F - i *100,E * 100)\),计算密度,和前一个比较就行 #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 putch…

最近感觉自己思维僵化,啥都不会做了-- ARC103 F Distance Sums 题意 给定第 \(i\) 个点到所有点的距离和 \(D_i\) ,要求构造一棵合法的树.满足第 \(i\) 个点到其他所有点的距离和为 \(D_i\) . \(n \le 10^5\) . 技巧 寻找特殊的量,推出整个树的形态 题解 题解 整棵树里头,最为特殊的点有两类.一个是重心,这是距离和最小的点,另一个是叶子节点,这是距离和最大的节点.考虑如果我们先确定重心,那么接着就不大好往下推了,因为我们并不知道子树…

构造题都是神仙题 /kk ARC066C Addition and Subtraction Hard 首先要发现两个性质: 加号右边不会有括号:显然,有括号也可以被删去,答案不变. \(op_i\)和\(A_{i+1}\)之间只会有一个括号:有多个括号的话只保留最外边那个,答案不变. 然后就可以定义状态:\(dp_{i,j}\)表示前\(i\)个数,还有\(j\)个未闭合的左括号,得到的最大答案. 由于只有减号右边有括号,所以只要知道左边有几个未闭合的左括号,就可以知道自己的贡献是\(1\)还是…

Time Limit: 10000MS   Memory Limit: 64000K Total Submissions: 5090   Accepted: 2529 Case Time Limit: 2000MS   Special Judge Description Ivan is fond of collecting. Unlike other people who collect post stamps, coins or other material stuff, he collect…

题目描述 Ivan is fond of collecting. Unlike other people who collect post stamps, coins or other material stuff, he collects software bugs. When Ivan gets a new program, he classifies all possible bugs into n categories. Each day he discovers exactly one…

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…

http://acm.csu.edu.cn/OnlineJudge/problem.php?id=1119 1119: Collecting Coins Time Limit: 3 Sec  Memory Limit: 128 MBSubmit: 144  Solved: 35[Submit][Status][Web Board] Description In a maze of r rows and c columns, your task is to collect as many coin…

安装的插件:Activiti 在Eclipse安装插件时,报以下错误: An error occurred while collecting items to be installed session context was:(profile=epp.package.jee, phase=org.eclipse.equinox.internal.p2.engine.phases.Collect, operand=, action=). Problems downloading artifact:…

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…

[POJ2096]Collecting Bugs Description Ivan is fond of collecting. Unlike other people who collect post stamps, coins or other material stuff, he collects software bugs. When Ivan gets a new program, he classifies all possible bugs into n categories. E…

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…

Collecting Bugs Time Limit: 10000MS   Memory Limit: 64000K Total Submissions: 1716   Accepted: 783 Case Time Limit: 2000MS   Special Judge Description Ivan is fond of collecting. Unlike other people who collect post stamps, coins or other material st…

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…

Collecting Bugs Time Limit: 10000MS   Memory Limit: 64000K Total Submissions: 3064   Accepted: 1505 Case Time Limit: 2000MS   Special Judge Description Ivan is fond of collecting. Unlike other people who collect post stamps, coins or other material s…

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…