Luogu4606 SDOI2018 战略游戏 圆方树虚树链并
Posted itst
tags:
篇首语:本文由小常识网(cha138.com)小编为大家整理,主要介绍了Luogu4606 SDOI2018 战略游戏 圆方树虚树链并相关的知识,希望对你有一定的参考价值。
考虑到去掉一个点使得存在两个点不连通的形式类似割点,不难想到建立圆方树。那么在圆方树上对于给出的关键点建立虚树之后,我们需要求的就是虚树路径上所有圆点的数量减去关键点的数量。
因为没有DP,所以其实没有必要将虚树建立起来,只需要维护一个链并就可以了。
#include<bits/stdc++.h>
//This code is written by Itst
using namespace std;
inline int read(){
int a = 0;
char c = getchar();
bool f = 0;
while(!isdigit(c) && c != EOF){
if(c == ‘-‘)
f = 1;
c = getchar();
}
if(c == EOF)
exit(0);
while(isdigit(c)){
a = a * 10 + c - 48;
c = getchar();
}
return f ? -a : a;
}
const int MAXN = 2e5 + 7;
int head[MAXN] , N , M , cnt , cntEd , ans;
int dfn[MAXN] , low[MAXN] , st[MAXN] , ts , top;
int ind[MAXN] , dep[MAXN] , TS;
vector < int > ch[MAXN];
int num[MAXN] , jump[MAXN][19];
struct Edge{
int end , upEd;
}Ed[MAXN << 1];
struct cmp{
bool operator ()(int a , int b){
return ind[a] < ind[b];
}
};
set < int , cmp > s;
set < int , cmp > :: iterator it1 , it2;
inline void addEd(int a , int b){
Ed[++cntEd].end = b;
Ed[cntEd].upEd = head[a];
head[a] = cntEd;
}
void pop(int x , int bot){
++cnt;
ch[cnt].clear();
ch[x].push_back(cnt);
do{
ch[cnt].push_back(st[top]);
}while(st[top--] != bot);
}
void tarjan(int x , int p){
dfn[x] = low[x] = ++ts;
st[++top] = x;
ch[x].clear();
for(int i = head[x] ; i ; i = Ed[i].upEd)
if(Ed[i].end != p)
if(!dfn[Ed[i].end]){
tarjan(Ed[i].end , x);
low[x] = min(low[x] , low[Ed[i].end]);
if(low[Ed[i].end] >= dfn[x])
pop(x , Ed[i].end);
}
else
low[x] = min(low[x] , dfn[Ed[i].end]);
}
void dfs(int x , int p){
ind[x] = ++TS;
dep[x] = dep[p] + 1;
jump[x][0] = p;
for(int i = 1 ; i <= 18 ; ++i)
jump[x][i] = jump[jump[x][i - 1]][i - 1];
num[x] = num[p] + (x <= N);
for(int i = 0 ; i < ch[x].size() ; ++i)
dfs(ch[x][i] , x);
}
inline int LCA(int x , int y){
if(dep[x] < dep[y])
swap(x , y);
for(int i = 18 ; i >= 0 ; --i)
if(dep[x] - (1 << i) >= dep[y])
x = jump[x][i];
if(x == y)
return x;
for(int i = 18 ; i >= 0 ; --i)
if(jump[x][i] != jump[y][i]){
x = jump[x][i];
y = jump[y][i];
}
return jump[x][0];
}
inline void insert(int x){
s.insert(x);
it1 = it2 = s.find(x);
int p = 0 , q = 0;
if(it1 != s.begin())
p = LCA(*(--it1) , x);
if(++it2 != s.end())
q = LCA(*it2 , x);
p = dep[p] < dep[q] ? q : p;
ans += num[x] - num[p];
}
int main(){
#ifndef ONLINE_JUDGE
freopen("in","r",stdin);
freopen("out","w",stdout);
#endif
for(int T = read() ; T ; --T){
cnt = N = read();
M = read();
memset(head , 0 , sizeof(head));
memset(dfn , 0 , sizeof(dfn));
cntEd = ts = TS = top = 0;
for(int i = 1 ; i <= M ; ++i){
int a = read() , b = read();
addEd(a , b);
addEd(b , a);
}
tarjan(1 , 0);
dfs(1 , 0);
for(int Q = read() ; Q ; --Q){
s.clear();
ans = 0;
int S = read() , t;
for(int i = 1 ; i <= S ; ++i){
int a = read();
if(i == 1)
t = a;
else
if(t != 1)
t = LCA(t , a);
insert(a);
}
printf("%d
" , ans - S - num[jump[t][0]]);
}
}
return 0;
}
以上是关于Luogu4606 SDOI2018 战略游戏 圆方树虚树链并的主要内容,如果未能解决你的问题,请参考以下文章