#include<bits/stdc++.h>
using namespace std;
//#include<ext/pb_ds/assoc_container.hpp>
//#include<ext/pb_ds/tree_policy.hpp>
//
// #pragma GCC optimize("unroll-loops")
// #pragma GCC optimize("Ofast")
// #pragma GCC optimize("-O3")
// #pragma GCC optimize("no-stack-protector")
// #pragma GCC optimize("fast-math")
//#pragma GCC optimize("Ofast")
//#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx")
//#define LOCAL
#define sim template < class c
#define ris return * this
#define dor > debug & operator <<
#define eni(x) sim > typename \
enable_if<sizeof dud<c>(0) x 1, debug&>::type operator<<(c i) {
sim > struct rge { c b, e; };
sim > rge<c> range(c i, c j) { return rge<c>{i, j}; }
sim > auto dud(c* x) -> decltype(cerr << *x, 0);
sim > char dud(...);
struct debug {
#ifndef LOCAL
~debug() { cerr << endl; }
eni(!=) cerr << boolalpha << i; ris; }
eni(==) ris << range(begin(i), end(i)); }
sim, class b dor(pair < b, c > d) {
ris << "(" << d.first << ", " << d.second << ")";
}
sim dor(rge<c> d) {
*this << "[";
for (auto it = d.b; it != d.e; ++it)
*this << ", " + 2 * (it == d.b) << *it;
ris << "]";
}
#else
sim dor(const c&) { ris; }
#endif
};
#define imie(...) " [" << #__VA_ARGS__ ": " << (__VA_ARGS__) << "] "
#define fi first
#define f first
#define se second
#define s second
#define vi_a vector<int>a;
#define p_b push_back
////////////////////////////////???????????????CHECK THIS OUT???????????????//////////////////////////////
#define ll long long
typedef unsigned long long ull;
////////////////////////////////???????????????CHECK THIS OUT???????????????//////////////////////////////
#define ld long double
#define pll pair<ll,ll>
#define pii pair<int,int>
#define m_p make_pair
#define fast_io cin.tie(0);cout.tie(0);ios_base::sync_with_stdio(0);
#define all(x) x.begin(),x.end()
#define getfiles ifstream cin("input.txt");ofstream cout("output.txt");
#define pw(x) (1ll << x)
#define sz(x) (int)x.size()
#define endl "\n"
#define rall(x) x.rbegin(),x.rend()
#define len(a) (ll)a.size()
#define rep(x,l,r) for(ll x=l;x<r;x++)
//using namespace __gnu_pbds;
ld eps = (ld)1 / 1e6;
const ld pi=3.14159265359;
ll inf = 1e18,mod1=1e9+7;
ll sqr(ll a) { return a * a; }
ll qb(ll a) { return a * a * a; }
ll gcd(ll a, ll b) { return !a ? b : gcd(b % a, a); }
ll binpow(ll a, ll b, ll mod) { return b ? (b % 2 ? (a * (sqr(binpow(a, b / 2, mod)) % mod)) % mod : sqr(binpow(a, b / 2, mod)) % mod) : 1; }
ll binmult(ll a, ll b, ll mod) { return b ? (b % 2 ? (2 * binmult(a, b / 2, mod) + a) % mod : (2 * binmult(a, b / 2, mod)) % mod) : 0; }
/////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
const ll tx[4]={0,0,-1,1};
const ll ty[4]={-1,1,0,0};
const char rev_to[4]={'E','W','N','S'};
const int M=1e9+7;
const int N=3e5+1;
const int ppp=73;
const int lg=19;
//typedef tree<ll,null_type,less<ll>,rb_tree_tag,tree_order_statistics_node_update> st;
auto rnd=bind(uniform_int_distribution<ll>(1,N),mt19937(time(0)));
void bad(){
cout<<"NE";
exit(0);
}
int l[N][lg],h[N],d[N],in[N],out[N],t=0;
vector<int>g[N];
void dfs(int v,int p,int gl){
d[v]=gl;
in[v]=++t;h[v]=d[v];
l[v][0]=p;
for(int i=1;i<lg;i++) l[v][i]=l[l[v][i-1]][i-1];
for(auto &z : g[v]){
if(z==p) continue;
dfs(z,v,gl+1);
}
out[v]=++t;
}
bool is(int a,int b){return in[a]<=in[b]&&out[a]>=out[b];}
int lca(int a,int b){
if(is(a,b)) return a;if(is(b,a)) return b;
for(int i=lg-1;i>=0;i--)if(!is(l[a][i],b))a=l[a][i];
return l[a][0];
}
vector<pii>adj[N];
/// u,colour;
void add_edge(int v,int u,int c){
adj[v].p_b({u,c});
adj[u].p_b({v,c});
}
int connect(int v,int p){
for(auto &u : g[v]){
if(u==p) continue;
int tmp=connect(u,v);
h[v]=min(h[v],tmp);
if(tmp<d[v]){
add_edge(v,u,0);
}
}
}
int clr[N];
bool is_ok(int v,int p,int colour){
if(clr[v]!=-1) return clr[v]==colour;
clr[v]=colour;
for(auto &z : adj[v]){
if(!is_ok(z.f,v,colour^z.s)) return 0;
}
return 1;
}
int n,m,v,u;
signed main()
{
fast_io;
fill(clr,clr+N,-1);
cin>>n>>m;
for(int i=1;i<n;i++){
cin>>v>>u;g[v].p_b(u);g[u].p_b(v);
}
dfs(1,1,0);
for(int i=0;i<m;i++){
cin>>v>>u;
int c=lca(v,u);
h[v]=min(h[v],d[c]);
h[u]=min(h[u],d[c]);
if(c^v && c^u){
add_edge(v,u,1);
}
}
connect(1,1);
ll ans=1;
for(int i=1;i<=n;i++){
if(clr[i]!=-1) continue;
if(!is_ok(i,i,0)) {ans=0;break;}
ans=((ans<<1)%M);
}
cout<<ans;
return 0;
}
/*
5 1
2 3 6 4 1
2 1 4
// 1,2,3,4,2 3,3 4
*/
Compilation message
usmjeri.cpp: In function 'int lca(int, int)':
usmjeri.cpp:104:5: warning: this 'if' clause does not guard... [-Wmisleading-indentation]
if(is(a,b)) return a;if(is(b,a)) return b;
^~
usmjeri.cpp:104:26: note: ...this statement, but the latter is misleadingly indented as if it were guarded by the 'if'
if(is(a,b)) return a;if(is(b,a)) return b;
^~
usmjeri.cpp: In function 'int connect(int, int)':
usmjeri.cpp:123:1: warning: no return statement in function returning non-void [-Wreturn-type]
}
^
| # |
결과 |
실행 시간 |
메모리 |
Grader output |
| 1 |
Incorrect |
116 ms |
34168 KB |
Output isn't correct |
| # |
결과 |
실행 시간 |
메모리 |
Grader output |
| 1 |
Incorrect |
239 ms |
70776 KB |
Output isn't correct |
| # |
결과 |
실행 시간 |
메모리 |
Grader output |
| 1 |
Incorrect |
10 ms |
15744 KB |
Output isn't correct |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
결과 |
실행 시간 |
메모리 |
Grader output |
| 1 |
Incorrect |
11 ms |
15872 KB |
Output isn't correct |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
결과 |
실행 시간 |
메모리 |
Grader output |
| 1 |
Incorrect |
14 ms |
16256 KB |
Output isn't correct |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
결과 |
실행 시간 |
메모리 |
Grader output |
| 1 |
Incorrect |
13 ms |
16256 KB |
Output isn't correct |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
결과 |
실행 시간 |
메모리 |
Grader output |
| 1 |
Incorrect |
373 ms |
54520 KB |
Output isn't correct |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
결과 |
실행 시간 |
메모리 |
Grader output |
| 1 |
Incorrect |
509 ms |
59000 KB |
Output isn't correct |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
결과 |
실행 시간 |
메모리 |
Grader output |
| 1 |
Incorrect |
520 ms |
59384 KB |
Output isn't correct |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
결과 |
실행 시간 |
메모리 |
Grader output |
| 1 |
Incorrect |
489 ms |
59512 KB |
Output isn't correct |
| 2 |
Halted |
0 ms |
0 KB |
- |
