CF191C Fools and Roads - 树剖解法
Codeforces Round #121 (Div. 1) C. Fools and Roads
time limit per test :2 seconds
memory limit per test : 256 megabytes
They say that Berland has exactly two problems, fools and roads. Besides, Berland has n cities, populated by the fools and connected by the roads. All Berland roads are bidirectional. As there are many fools in Berland, between each pair of cities there is a path (or else the fools would get upset). Also, between each pair of cities there is no more than one simple path (or else the fools would get lost).
But that is not the end of Berland's special features. In this country fools sometimes visit each other and thus spoil the roads. The fools aren't very smart, so they always use only the simple paths.
A simple path is the path which goes through every Berland city not more than once.
The Berland government knows the paths which the fools use. Help the government count for each road, how many distinct fools can go on it.
Note how the fools' paths are given in the input.
Input
The first line contains a single integer n (2 ≤ n ≤ 105) — the number of cities.
Each of the next n - 1 lines contains two space-separated integers u**i, v**i (1 ≤ u**i, v**i ≤ n, u**i ≠ v**i), that means that there is a road connecting cities u**i and v**i.
The next line contains integer k (0 ≤ k ≤ 105) — the number of pairs of fools who visit each other.
Next k lines contain two space-separated numbers. The i-th line (i > 0) contains numbers a**i, b**i (1 ≤ a**i, b**i ≤ n). That means that the fool number 2i - 1 lives in city a**i and visits the fool number 2i, who lives in city b**i. The given pairs describe simple paths, because between every pair of cities there is only one simple path.
Output
Print n - 1 integer. The integers should be separated by spaces. The i-th number should equal the number of fools who can go on the i-th road. The roads are numbered starting from one in the order, in which they occur in the input.
Examples
Input
5
1 2
1 3
2 4
2 5
2
1 4
3 5
Output
2 1 1 1
Input
5
3 4
4 5
1 4
2 4
3
2 3
1 3
3 5
Output
3 1 1 1
Note
In the first sample the fool number one goes on the first and third road and the fool number 3 goes on the second, first and fourth ones.
In the second sample, the fools number 1, 3 and 5 go on the first road, the fool number 5 will go on the second road, on the third road goes the fool number 3, and on the fourth one goes fool number 1.
题目大意
给你一棵树,然后给你k个操作,每次操作输入两个整数a b
表示从a 走到b的边的权值都加1
一开始所有权值都为0
最后输出每条边的权值, 按照边输入的顺序
n <= 10^5
Solution
显然树链剖分可做
把边权该做下面的(dep深)的点权。
这样就处理好了
然后在跑一下树链剖分,注意公共祖先不能赋值。
在做的过程中注意边的编号要记录
然后就好了
code
#include<bits/stdc++.h>
#define DEBUG cerr << "Call out at function: " << __func__ << ", In line: " << __LINE__ << " --- "
using namespace std;
vector <int> f[110000];
vector <int> g[110000];
int n;
int w[110000];
int son[110000];
int seg[110000];int pl;
int rev[110000];
int dep[110000];
int top[110000];
int fa[110000];
int id[110000];
long long C[110000];
inline int lowbit(int x){
return x & (-x);
}
void add(int x,long long v){
while (x > 0) C[x] += v, x -= lowbit(x);
}
long long query(int x){
long long ret = 0;
while (x <= n) ret += C[x], x += lowbit(x);
return ret;
}
int DFS1(int fat,int x)
{
fa[x] = fat;
w[x] = 1;
dep[x] = dep[fat] + 1;
int MAX = 0;
for (int i=0;i<f[x].size();i++)
if (f[x][i] != fat){
id[g[x][i]] = f[x][i];
int tmp = DFS1(x,f[x][i]);
w[x] += tmp;
if (tmp > MAX)
son[x] = f[x][i], MAX = tmp;
}
return w[x];
}
void DFS2(int x){
seg[x] = ++pl;
rev[pl] = x;
if (son[x] == 0) return;
top[son[x]] = top[x];
DFS2(son[x]);
for (int i=0;i<f[x].size();i++){
if (f[x][i] != son[x] && f[x][i] != fa[x])
top[f[x][i]] = f[x][i], DFS2(f[x][i]);
}
}
int add(int x,int y,long long val){
while (top[x] != top[y]){
if (dep[top[x]] < dep[top[y]])
swap(x,y);
add(seg[x],1);
add(seg[top[x]]-1,-1);
x = fa[top[x]];
}
if (dep[x] > dep[y])
swap(x,y);
add(seg[y],1);
add(seg[x],-1);
}
int main()
{
cin >> n;
for (int i=1;i<n;i++){
int tp1,tp2;
cin >> tp1 >> tp2;
f[tp1].push_back(tp2);
f[tp2].push_back(tp1);
g[tp1].push_back(i);
g[tp2].push_back(i);
}
DFS1(-1,1);
top[1] = 1,DFS2(1);
int m;
cin >> m;
for (int i=1;i<=m;i++){
int tp1,tp2;
cin >> tp1 >> tp2;
add(tp1,tp2,1);
}
for (int i=1;i<=n-1;i++)
cout << query(seg[id[i]]) << ' ';
}
CF191C Fools and Roads - 树剖解法的更多相关文章
- Codeforces 191C Fools and Roads(树链拆分)
题目链接:Codeforces 191C Fools and Roads 题目大意:给定一个N节点的数.然后有M次操作,每次从u移动到v.问说每条边被移动过的次数. 解题思路:树链剖分维护边,用一个数 ...
- Codeforces 191 C Fools and Roads (树链拆分)
主题链接~~> 做题情绪:做了HDU 5044后就感觉非常easy了. 解题思路: 先树链剖分一下,把树剖分成链,由于最后全是询问,so~能够线性操作.经过树链剖分后,就会形成很多链,可是每条边 ...
- [CF191C]Fools and Roads
题目大意:有一颗$n$个节点的树,$k$次旅行,问每一条被走过的次数. 题解:树上差分,$num_x$表示连接$x$和$fa_x$的边被走过的次数,一条路径$u->v$,$num_u+1,num ...
- CF 191C Fools and Roads lca 或者 树链剖分
They say that Berland has exactly two problems, fools and roads. Besides, Berland has n cities, popu ...
- [CTSC2008]网络管理(整体二分+树剖+树状数组)
一道经典的带修改树链第 \(k\) 大的问题. 我只想出三个 \(\log\) 的解法... 整体二分+树剖+树状数组. 那不是暴力随便踩的吗??? 不过跑得挺快的. \(Code\ Below:\) ...
- 2017多校第9场 HDU 6162 Ch’s gift 树剖加主席树
题目链接:http://acm.hdu.edu.cn/showproblem.php?pid=6162 题意:给出一棵树的链接方法,每个点都有一个数字,询问U->V节点经过所有路径中l < ...
- HDU 6162 Ch’s gift (树剖 + 离线线段树)
Ch’s gift Time Limit: 6000/3000 MS (Java/Others) Memory Limit: 65536/65536 K (Java/Others)Total S ...
- 51nod1307(暴力树剖/二分&dfs/并查集)
题目链接: http://www.51nod.com/onlineJudge/questionCode.html#!problemId=1307 题意: 中文题诶~ 思路: 解法1:暴力树剖 用一个数 ...
- POJ2763 Housewife Wind(树剖+线段树)
After their royal wedding, Jiajia and Wind hid away in XX Village, to enjoy their ordinary happy lif ...
随机推荐
- linux 更改文件权限命令 chmod
chmod -change file mode bits :更改文件权限 chmod是用来改变文件或者目录权限的命令,但只有文件的属主和超级用户(root)才有这种权限. 更改文件权限的2种方式: 一 ...
- P1142轰炸
这是uva上的一道模拟题. 首先给出n(n<=700)个点的坐标(坐标在1*10^9)之内,询问走直线可以经过的点数.一开始我想到了一个类似于桶排序的方法来存坐标,但是要注意数组大小啊!第二次想 ...
- 赛道修建 NOIP 2018 d1t3
题目大意 最小值最大 考虑二分 二分答案 判断能不能构成m条路径 很明显满足单调性 可行 思考如何判断 对于一个节点 它的儿子会传上来一些路径 这些路径只有三种处理方式 一.传上去(只能传一条) 二. ...
- python之入门
第一章 入门 1.1 变量-输出 a = 1 # 声明变量 a # 变量的名字 = # 赋值 1 # 值 变量定义的规则: 1.变量由数字,字母,下划线组成 2.不能以数字开头 3.不能使用pytho ...
- selenium之京东商品爬虫
#今日目标 **selenium之京东商品爬虫** 自动打开京东首页,并输入你要搜索的东西,进入界面进行爬取信息 ``` from selenium import webdriver import t ...
- python之self的理解
一.self的位置是出现在哪里? 首先,self是在类的方法中的,在调用此方法时,不用给self赋值,Python会自动给他赋值,而且这个值就是类的实例--对象本身.也可以将self换成别的叫法例如s ...
- a页面通过url传值,b页面如何接收(jquery.params.js实现)
用于两个html页面之间的传值 我的应用场景是:用echarts在a页面做完中国地图后,点击某个省份在b页面显示某个省份的地图.(在b页面显示点击了的那个省份的地图,等于说b页面是个“容器”页) 假设 ...
- 实现 RSA 算法之改进和优化(第三章)(老物)
第三章 如何改进和优化RSA算法 这章呢,我想谈谈在实际应用出现的问题和理解. 由于近期要开始各种忙了,所以写完这章后我短时间内也不打算出什么资料了=- =(反正平时就没有出资料的习惯.) 在讲第一章 ...
- Linux上安装ElasticSearch及遇到的问题
在Linux上安装ElasticSearch 1. 安装前环境准备 安装JDK环境,并配置环境变量,这里可以参考我以前写过的博客 https://www.cnblogs.com/ywb-article ...
- sql server查询在线用户
select request_session_id spid, object_name(resource_associated_entity_id) tableName from sys.dm_tra ...