题目链接:点击传送 E. Propagating tree time limit per test 2 seconds memory limit per test 256 megabytes input standard input output standard output Iahub likes trees very much. Recently he discovered an interesting tree named propagating tree. The tree consi…
C. Propagating tree Time Limit: 20 Sec Memory Limit: 256 MB 题目连接 http://codeforces.com/contest/383/problem/C Description Iahub likes trees very much. Recently he discovered an interesting tree named propagating tree. The tree consists of n nodes numb…
C. Propagating tree Time Limit: 20 Sec Memory Limit: 256 MB 题目连接 http://codeforces.com/contest/383/problem/C Description Iahub likes trees very much. Recently he discovered an interesting tree named propagating tree. The tree consists of n nodes numb…
D. Water Tree Time Limit: 1 Sec Memory Limit: 256 MB 题目连接 http://codeforces.com/contest/343/problem/D Description Mad scientist Mike has constructed a rooted tree, which consists of n vertices. Each vertex is a reservoir which can be either empty or…
D. Water Tree   Mad scientist Mike has constructed a rooted tree, which consists of n vertices. Each vertex is a reservoir which can be either empty or filled with water. The vertices of the tree are numbered from 1 to n with the root at vertex 1. Fo…
POJ.3321 Apple Tree ( DFS序 线段树 单点更新 区间求和) 题意分析 卡卡屋前有一株苹果树,每年秋天,树上长了许多苹果.卡卡很喜欢苹果.树上有N个节点,卡卡给他们编号1到N,根的编号永远是1.每个节点上最多结一个苹果.卡卡想要了解某一个子树上一共结了多少苹果. 现在的问题是不断会有新的苹果长出来,卡卡也随时可能摘掉一个苹果吃掉.你能帮助卡卡吗? 前缀技能 边表存储树 DFS时间戳 线段树 首先利用边表将树存储下来,然后DFS打上时间戳.打上时间戳之后,我们就知道书上节点对…
D. Babaei and Birthday Cake 题目连接: http://www.codeforces.com/contest/629/problem/D Description As you know, every birthday party has a cake! This time, Babaei is going to prepare the very special birthday party's cake. Simple cake is a cylinder of som…
题目链接:http://codeforces.com/contest/474/problem/F 题意简而言之就是问你区间l到r之间有多少个数能整除区间内除了这个数的其他的数,然后区间长度减去数的个数就是答案. 要是符合条件的话,那这个数的大小一定是等于gcd(a[l]...a[r]). 我们求区间gcd的话,既可以利用线段树性质区间递归下去然后返回求解,但是每次查询是log的,所以还可以用RMQ,查询就变成O(1)了. 然后求解区间内有多少个数的大小等于gcd的话,也是利用线段树的性质,区间递…
C. Day at the Beach Time Limit: 20 Sec Memory Limit: 256 MB 题目连接 http://codeforces.com/contest/599/problem/C Description One day Squidward, Spongebob and Patrick decided to go to the beach. Unfortunately, the weather was bad, so the friends were unab…
D. The Child and Sequence Time Limit: 20 Sec Memory Limit: 256 MB 题目连接 http://codeforces.com/contest/438/problem/D Description At the children's day, the child came to Picks's house, and messed his house up. Picks was angry at him. A lot of important…
题意:做蛋糕,给出N个半径,和高的圆柱,要求后面的体积比前面大的可以堆在前一个的上面,求最大的体积和. 思路:首先离散化蛋糕体积,以蛋糕数量建树建树,每个节点维护最大值,也就是假如节点i放在最上层情况下的体积最大值dp[i].每次查询比蛋糕i小且最大体积的蛋糕,然后更新线段树.注意此题查询的技巧!!查询区间不变l,r,才能保证每次查到的是小且最大体积. #include<iostream> #include<string> #include<algorithm> #in…
题目地址:http://codeforces.com/contest/474/problem/F 由题意可知,最后能够留下来的一定是区间最小gcd. 那就转化成了该区间内与区间最小gcd数相等的个数.区间最小gcd一定小于等于区间最小值.所以仅仅要先推断最小值是否是最小gcd.若是的话,就求出最小值的个数.然后用r-l+1-个数就可以. 对于以上信息.能够用线段树来维护.分别维护区间gcd,区间最小值以及区间最小值的个数. 代码例如以下: #include <iostream> #includ…
https://codeforces.com/contest/1062/problem/E 题意 给一颗树n,然后q个询问,询问编号l~r的点,假设可以删除一个点,使得他们的最近公共祖先深度最大.每次询问,输出删除的点和祖先的深度 思路 考虑dfs序来判断v是否在u的子树里: dfn[u]<dfn[v]<=max(dfn[u的子树]) 那么进一步拓展,dfs序之差越大,点就在越分离的地方,这些点的lca一定是lca(max(dfn[u]),min(dfn[u])) 这不仅知道了需要去掉哪个点(…
传送门 D. R2D2 and Droid Army time limit per test 2 seconds memory limit per test 256 megabytes input standard input output standard output An army of n droids is lined up in one row. Each droid is described by m integers a1, a2, ..., am, where ai is th…
Apple Tree Time Limit: 2000MS   Memory Limit: 65536K       Description There is an apple tree outside of kaka's house. Every autumn, a lot of apples will grow in the tree. Kaka likes apple very much, so he has been carefully nurturing the big apple t…
Apple Tree:http://poj.org/problem?id=3321 题意: 告诉你一棵树,每棵树开始每个点上都有一个苹果,有两种操作,一种是计算以x为根的树上有几个苹果,一种是转换x这个点上的苹果,就是有就去掉,没有就加上. 思路: 先对树求一遍dfs序,每个点保存一个l,r.l是最早到这个点的时间戳,r是这个点子树中的最大时间戳,这样就转化为区间问题,可以用树状数组,或线段树维护区间的和. #include <algorithm> #include <iterator&…
B. "Or" Game Time Limit: 1 Sec Memory Limit: 256 MB 题目连接 http://codeforces.com/contest/578/problem/B Description You are given n numbers a1, a2, ..., an. You can perform at most k operations. For each operation you can multiply one of the number…
题:https://codeforces.com/contest/1099/problem/F 题意:给定一个树,每个节点有俩个信息x和t,分别表示这个节点上的饼干个数和先手吃掉这个节点上一个饼干的的时间.然后有先手和后手俩个人. ◉先手可以这么操作:在规定总时间T到达某个节点然后一定要返回根节点1,期间可以选择吃掉某些节点上的某些饼干(前提是保证剩下的时间能够回到根节点): ◉后手可以这么操作:在先手到达的位置和这个位置的孩子之间的连边选择一条让先手吃得更多的边摧毁掉,也可以跳过这个过程: 问…
题目链接:http://codeforces.com/problemset/problem/438/D 给你n个数,m个操作,1操作是查询l到r之间的和,2操作是将l到r之间大于等于x的数xor于x,3操作是将下标为k的数变为x. 注意成段更新的时候,遇到一个区间的最大值还小于x的话就停止更新. #include <iostream> #include <cstdio> #include <cstring> using namespace std; typedef __…
题意 给出一个长度为 \(n\) 的序列 \(\{a_i\}\) , 现在会进行 \(m\) 次操作 , 每次操作会修改某个 \(a_i\) 的值 , 在每次操作完后你需要判断是否存在一个位置 \(i\), 满足 \(\displaystyle a_i = \sum_{j=1}^{i - 1}a_j\) 并求任意一个 \(i\) . \(n, m ≤ {10}^5 , 0 ≤ a_i ≤ {10}^9\) 题解 考虑一个暴力,不妨首先从 \(i = 1\) 开始判断是否合法,由于 \(a_i\)…
E. Kefa and Watch time limit per test 1 second memory limit per test 256 megabytes input standard input output standard output One day Kefa the parrot was walking down the street as he was on the way home from the restaurant when he saw something gli…
D. The Child and Sequence   At the children's day, the child came to Picks's house, and messed his house up. Picks was angry at him. A lot of important things were lost, in particular the favorite sequence of Picks. Fortunately, Picks remembers how t…
E. Correct Bracket Sequence Editor   Recently Polycarp started to develop a text editor that works only with correct bracket sequences (abbreviated as CBS). Note that a bracket sequence is correct if it is possible to get a correct mathematical expre…
[链接]我是链接 [题意] 接上一篇文章 [题解] 接(点我进入)上一篇文章. 这里讲一种用类似二维线段树的方法求矩形区域内点的个数的方法. 我们可以把n个正方形用n棵线段树来维护. 第i棵线段树维护的是正方形的前i列的各行之间的点数之和. 也即前i列,第[x..y]行之间点的个数(也即一个(y-x+1)*i的矩形区域的点的个数); 因为每一列只有一个点. 所以,我们在输入的时候,当前的"行区间l..r"的点数和,直接加上1就好. 然后看看输入的点所在的行区间在l..m还是m+1..r…
E. New Year Treetime limit per test3 secondsmemory limit per test256 megabytesinputstandard inputoutputstandard outputThe New Year holidays are over, but Resha doesn't want to throw away the New Year tree. He invited his best friends Kerim and Gural…
题目链接 给一棵树, 每个节点有颜色, 两种操作, 一种是将一个节点的子树全都染色成c, 一种是查询一个节点的子树有多少个不同的颜色, c<=60. 每个节点一个bitset维护就可以. #include <iostream> #include <vector> #include <cstdio> #include <cstring> #include <algorithm> #include <cmath> #include…
PSHTTR: Pishty 和城堡题目描述 Pishty 是生活在胡斯特市的一个小男孩.胡斯特是胡克兰境内的一个古城,以其中世纪风格 的古堡和非常聪明的熊闻名全国. 胡斯特的镇城之宝是就是这么一座古堡,历史上胡斯特依靠这座古堡抵挡住了疯人国的大军. 对于 Pishty 来说,真正吸引他的是古堡悠长的走廊和高耸的钟楼,以及深藏于其中的秘密…… 古堡可以用一棵 N 个节点的树的描述,树中有 N −1 条无向边,每条边有一个魔法数字 C. 当一个旅游团参观古堡时,他们会选择树上 U 到 V 的路径游…
题目链接   Danil and a Part-time Job 题意    给出一系列询问或者修改操作 $pow$ $x$表示把以$x$为根的子树的所有结点的状态取反($0$变$1$,$1$变$0$) $get$  $x$表示求以$x$为根的子树中状态为$1$的结点数. 首先大力$dfs$序,然后线段树操作一下. 具体问题转化为:区间翻转,区间求和. #include <bits/stdc++.h> using namespace std; #define rep(i, a, b) for…
A. Alex and broken contest time limit per test 2 seconds memory limit per test 256 megabytes input standard input output standard output One day Alex was creating a contest about his friends, but accidentally deleted it. Fortunately, all the problems…
题意:给出一颗有根树的构造和一开始每个点的颜色 有两种操作 1 : 给定点的子树群体涂色 2 : 求给定点的子树中有多少种颜色 比较容易想到dfs序+线段树去做 dfs序是很久以前看的bilibili上电子科技大学发的视频学习的 将一颗树通过dfs编号的方式 使每个点的子树的编号连在一起作为相连的区间 就可以配合线段树搞子树 因为以前好像听说过 线段树可以解决一种区间修改和查询区间中不同的xx个数...所以一下子就想到了... 但是我不会写线段树..只会最简单的单点修改区间查询...不会用延迟标…