QOJ.ac
QOJ
ID | 题目 | 提交者 | 结果 | 用时 | 内存 | 语言 | 文件大小 | 提交时间 | 测评时间 |
---|---|---|---|---|---|---|---|---|---|
#783803 | #8078. Spanning Tree | fsdhmbb# | WA | 79ms | 45200kb | C++14 | 1.9kb | 2024-11-26 11:50:37 | 2024-11-26 11:50:47 |
Judging History
answer
#include <bits/stdc++.h>
#define int long long
using namespace std;
typedef long long ll;
const int maxn=1e6+5;
const int mod=998244353;
vector <int> mp[maxn];
int l[maxn],r[maxn];
int fa[maxn],siz[maxn];
long long a,b,p;
long long quickPower(long long a,long long b,long long p)
{
long long ans=1,base=a;
while (b>0)
{
if(b&1==1){
ans*=base;
ans%=p;
}
base*=base;
base%=p;
b>>=1;
}
return ans;
}
void dfs(int u,int f)
{
fa[u]=f;
for(auto v:mp[u])
{
if(v!=f)
{
dfs(v,u);
}
}
}
struct BCJ
{
int fa[maxn];
void init(int n)
{
for(int i=1;i<=n;i++)
{
fa[i]=i;
siz[i]=1;
}
}
int findfa(int x)
{
if(x==fa[x])
{
return x;
}
return fa[x]=findfa(fa[x]);
}
void merge(int a,int b)
{
fa[a]=findfa(b);
siz[b]+=siz[a];
}
}bcj;
signed main()
{
int n;
cin>>n;
for(int i=1;i<n;i++)
{
cin>>l[i]>>r[i];
}
for(int i=1;i<n;i++)
{
int u,v;
cin>>u>>v;
mp[u].push_back(v);
mp[v].push_back(u);
}
bcj.init(n);
dfs(1,1);
int cnt=1;
for(int i=1;i<n;i++)
{
if(bcj.findfa(l[i])==bcj.findfa(r[i]))
{
cout<<"0\n";
return 0;
}
if((bcj.findfa(fa[bcj.findfa(l[i])])==bcj.findfa(r[i]))||(bcj.findfa(fa[bcj.findfa(r[i])])==bcj.findfa(l[i])))
{
cnt=cnt*siz[bcj.findfa(l[i])]%mod*siz[bcj.findfa(r[i])]%mod;
bcj.merge(bcj.findfa(l[i]),bcj.findfa(r[i]));
}
else
{
cout<<"0\n";
return 0;
}
}
//cout<<cnt<<"\n";
cout<<quickPower(cnt,mod-2,mod)<<"\n";
return 0;
}
詳細信息
Test #1:
score: 100
Accepted
time: 0ms
memory: 36824kb
input:
3 1 2 1 3 1 2 1 3
output:
499122177
result:
ok single line: '499122177'
Test #2:
score: -100
Wrong Answer
time: 79ms
memory: 45200kb
input:
100000 2183 5543 22424 59062 8387 24544 14668 74754 15788 58136 26846 99981 13646 57752 29585 62862 27383 65052 2013 13116 24490 91945 26006 61595 19000 78817 31371 67837 29311 82989 4298 20577 23212 77962 16510 85839 26010 98714 25314 96063 17206 82359 7478 76540 13890 99556 23277 64321 25684 92613...
output:
0
result:
wrong answer 1st lines differ - expected: '330864231', found: '0'