#include <bits/stdc++.h>
using namespace std;
#ifdef LOCAL
#include "algo/debug.h"
#endif
#define f first
#define s second
template<class T> using V = vector<T>;
using vi = V<int>;
using vb = V<bool>;
using vs = V<string>;
#define all(x) begin(x), end(x)
#define rall(x) rbegin(x), rend(x)
#define len(x) (int)((x).size())
#define rsz resize
#define ins insert
#define ft front()
#define bk back()
#define pb push_back
#define lb lower_bound
#define ub upper_bound
template<class T> int lwb(V<T>& a, const T& b) { return lb(all(a),b)-begin(a); }
template<class T> int upb(V<T>& a, const T& b) { return ub(all(a),b)-begin(a); }
template<class T> bool ckmin(T& a, const T& b) { return a > b ? a=b, true : false; }
template<class T> bool ckmax(T& a, const T& b) { return a < b ? a=b, true : false; }
#define pct __builtin_popcount
#define ctz __builtin_ctz
#define clz __builtin_clz
constexpr int p2(int x) { return (int)1 << x; }
constexpr int bits(int x) { return x == 0 ? 0 : 31-clz(x); } // floor(log2(x))
using i64 = long long;
template<class T>
constexpr T power(T a, i64 b) {
T res {1};
for (; b; b /= 2, a *= a) {
if (b % 2) {
res *= a;
}
}
return res;
}
constexpr i64 mul(i64 a, i64 b, i64 p) {
i64 res = a * b - i64(1.L * a * b / p) * p;
res %= p;
if (res < 0) {
res += p;
}
return res;
}
template<i64 P>
struct MInt {
i64 x;
constexpr MInt() : x {0} {}
constexpr MInt(i64 x) : x {norm(x % getMod())} {}
static inline i64 Mod;
constexpr static i64 getMod() {
if (P > 0) {
return P;
} else {
return Mod;
}
}
constexpr static void setMod(i64 Mod_) {
Mod = Mod_;
}
constexpr i64 norm(i64 x) const {
if (x < 0) {
x += getMod();
}
if (x >= getMod()) {
x -= getMod();
}
return x;
}
constexpr i64 val() const {
return x;
}
constexpr MInt operator-() const {
MInt res;
res.x = norm(getMod() - x);
return res;
}
constexpr MInt inv() const {
return power(*this, getMod() - 2);
}
constexpr MInt &operator*=(MInt rhs) & {
if (getMod() < (1ULL << 31)) {
x = x * rhs.x % int(getMod());
} else {
x = mul(x, rhs.x, getMod());
}
return *this;
}
constexpr MInt &operator+=(MInt rhs) & {
x = norm(x + rhs.x);
return *this;
}
constexpr MInt &operator-=(MInt rhs) & {
x = norm(x - rhs.x);
return *this;
}
constexpr MInt &operator/=(MInt rhs) & {
return *this *= rhs.inv();
}
friend constexpr MInt operator*(MInt lhs, MInt rhs) {
MInt res = lhs;
res *= rhs;
return res;
}
friend constexpr MInt operator+(MInt lhs, MInt rhs) {
MInt res = lhs;
res += rhs;
return res;
}
friend constexpr MInt operator-(MInt lhs, MInt rhs) {
MInt res = lhs;
res -= rhs;
return res;
}
friend constexpr MInt operator/(MInt lhs, MInt rhs) {
MInt res = lhs;
res /= rhs;
return res;
}
friend constexpr std::istream &operator>>(std::istream &is, MInt &a) {
i64 v = 69;
is >> v;
a = MInt(v);
return is;
}
friend constexpr std::ostream &operator<<(std::ostream &os, const MInt &a) {
return os << a.val();
}
friend constexpr bool operator==(MInt lhs, MInt rhs) {
return lhs.val() == rhs.val();
}
friend constexpr bool operator!=(MInt lhs, MInt rhs) {
return lhs.val() != rhs.val();
}
friend constexpr bool operator<(MInt lhs, MInt rhs) {
return lhs.val() < rhs.val();
}
};
template<>
i64 MInt<0>::Mod = 998244353;
constexpr int P = 1000000007;
using Z = MInt<P>;
Z ans=1;
const int LOG=19;
V<vi>up,g;
V<V<array<int,2>>>G;
vi dep,high,clr;
void init_lca(int u,int p){
for(int v:g[u])if(v!=p){
up[v][0]=u;
for(int i=1;i<LOG;i++){
up[v][i]=up[up[v][i-1]][i-1];
}
dep[v]=dep[u]+1;
init_lca(v,u);
}
}
int jump(int u,int x){
for(int i=LOG-1;i>=0;i--)if(x&p2(i)){
u=up[u][i];
}
return u;
}
int get_lca(int u,int v){
if(dep[u]<dep[v])swap(u,v);
u=jump(u,dep[u]-dep[v]);
if(u==v)return u;
for(int i=LOG-1;i>=0;i--)if(up[u][i]!=up[v][i]){
u=up[u][i];
v=up[v][i];
}
return up[u][0];
}
int connect(int u,int p){
for(int v:g[u])if(v!=p){
int tmp=connect(v,u);
ckmin(high[u],tmp);
if(tmp<dep[u]){
G[u].pb({v,0});
G[v].pb({u,0});
}
}
return high[u];
}
bool dfs(int u,int c){
if(clr[u]!=-1)return clr[u]==c;
clr[u]=c;
for(auto[v,typ]:G[u])if(!dfs(v,c^typ))return false;
return true;
}
void solve() {
int n,q;cin>>n>>q;
g.resize(n);
dep.rsz(n);
up.rsz(n,vi(LOG));
clr.rsz(n,-1);
high.rsz(n);
G.rsz(n);
for(int i=0;i<n-1;i++){
int u,v;cin>>u>>v;u--;v--;
g[u].pb(v);g[v].pb(u);
}
init_lca(0,-1);
for(int u=0;u<n;u++)high[u]=dep[u];
while(q--){
int u,v;cin>>u>>v;u--;v--;
int lca=get_lca(u,v);
ckmin(high[u],dep[lca]);
ckmin(high[v],dep[lca]);
if(lca!=u&&lca!=v){
G[u].pb({v,1});
G[v].pb({u,1});
}
while(u!=lca&&up[u][0]!=lca){
G[u].pb({up[u][0],0});
G[up[u][0]].pb({u,0});
u=up[u][0];
}
while(v!=lca&&up[v][0]!=lca){
G[v].pb({up[v][0],0});
G[up[v][0]].pb({v,0});
v=up[v][0];
}
}
connect(0,-1);
for(int u=1;u<n;u++)if(clr[u]==-1){
if(!dfs(u,0))ans=0;
else ans*=2;
}
cout<<ans<<'\n';
}
signed main() {
ios::sync_with_stdio(false);
cin.tie(0); cout.tie(0);
solve();
return 0;
}
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Runtime error |
352 ms |
262144 KB |
Execution killed with signal 9 |
2 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Runtime error |
361 ms |
262144 KB |
Execution killed with signal 9 |
2 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
2 ms |
604 KB |
Output is correct |
2 |
Correct |
2 ms |
856 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
2 ms |
604 KB |
Output is correct |
2 |
Correct |
1 ms |
860 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
4 ms |
1628 KB |
Output is correct |
2 |
Correct |
3 ms |
1372 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
4 ms |
1628 KB |
Output is correct |
2 |
Correct |
3 ms |
1372 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Runtime error |
887 ms |
262144 KB |
Execution killed with signal 9 |
2 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Runtime error |
897 ms |
262144 KB |
Execution killed with signal 9 |
2 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Runtime error |
933 ms |
262144 KB |
Execution killed with signal 9 |
2 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Runtime error |
960 ms |
262144 KB |
Execution killed with signal 9 |
2 |
Halted |
0 ms |
0 KB |
- |