//{ <defines>
#include <bits/stdc++.h>
using namespace std;
//#pragma comment(linker, "/stack:200000000")
//#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,tune=native")
//#pragma GCC optimize("Ofast,no-stack-protector,unroll-loops,fast-math,-O3")
#define fr(i, n) for(int i = 0; i < n; ++i)
#define fo(n) fr(i, n)
#define re return
#define ef else if
#define ifn(x) if(!(x))
#define _ << ' ' <<
#define ft first
#define sd second
#define ve vector
#define pb push_back
#define eb emplace_back
#define sz(x) int((x).size())
#define bnd(x) x.begin(), x.end()
#define clr(x, y) memset((x), (y), sizeof (x))
typedef long long ll;
typedef long double ld;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;
typedef ve<int> vi;
inline ll time() {re chrono :: system_clock().now().time_since_epoch().count();}
mt19937 rnd(time());
mt19937_64 RND(time());
template<typename t> inline void umin(t &a, t b) {a = min(a, b);}
template<typename t> inline void umax(t &a, t b) {a = max(a, b);}
int md = 998244353;
inline int m_add(int&a, int b) {a += b; if(a < 0) a += md; if(a >= md) a -= md; re a;}
inline int m_sum(int a, int b) {a += b; if(a < 0) a += md; if(a >= md) a -= md; re a;}
inline int m_mul(int&a, int b) {re a = 1ll * a * b % md;}
inline int m_prod(int a, int b) {re 1ll * a * b % md;}
int m_bpow(ll A, ll b) {
int a = A % md;
ll ans = 1;
for(ll p = 1ll << 63 - __builtin_clzll(b); p; p >>= 1) {
(ans *= ans) %= md;
if(p & b)
(ans *= a) %= md;
}
re ans;
}
//const ld pi = arg(complex<ld>(-1, 0));
//const ld pi2 = pi + pi;
const int oo = 2e9;
const ll OO = 4e18;
//} </defines>
const int N = 3e5 + 5;
int n, m;
vi g[N];
int p[N][19];
int l[N], r[N], timer;
int h[N], d[N], pr[N];
bool mk[N];
char col[N];
bool zero;
void paint(int v, char c) {
if(mk[v] && col[v] != c) zero = true;
if(mk[v]) re; mk[v] = true;
for(int u : g[v]) paint(u, !c);
}
int get(int x) {re d[x] == x ? x : d[x] = get(d[x]);}
void unite(int x, int y) {d[get(x)] = get(y);}
void rec(int v = 0, int pr = 0, int he = 0) {
h[v] = he;
l[v] = timer++;
p[v][0] = pr;
for(int i = 1; i < 19; ++i) p[v][i] = p[p[v][i - 1]][i - 1];
if(v) g[v].erase(find(bnd(g[v]), pr));
for(int u : g[v]) rec(u, v, he + 1);
r[v] = timer - 1;
}
inline bool pred(int u, int d) {re l[u] <= l[d] && r[u] >= r[d];}
inline int lca(int a, int b) {
for(int i = 18; ~i; --i)
if(!pred(p[a][i], b)) a = p[a][i];
re p[a][0];
}
void find(int v) {
if(!v) re;
int &u = pr[v];
if(get(u) == get(v)) {
find(u);
u = pr[u];
}
}
void path(int u, int v) {
find(v);
while(h[u] < h[pr[v]]) {
unite(v, pr[v]);
find(v = pr[v]);
}
}
void solve() {
timer = 0;
fo(n) g[i].clear();
cin >> n >> m;
fo(n - 1) {
int x, y;
cin >> x >> y;
--x, --y;
g[x].pb(y);
g[y].pb(x);
}
rec();
for(int i = 0; i < n; ++i) pr[i] = p[i][0];
for(int i = 1; i < n; ++i) d[i] = i;
ve<pii> c;
fo(m) {
int x, y;
cin >> x >> y;
--x, --y;
if(x == y) continue;
if(l[x] > l[y]) swap(x, y);
if(r[x] >= r[y]) {
path(x, y);
} else {
int z = lca(x, y);
path(z, x);
path(z, y);
c.eb(x, y);
}
}
zero = false;
for(int i = 0; i < n; ++i) g[i].clear();
for(pii f : c) {
int x = get(f.ft);
int y = get(f.sd);
if(x == y) zero = true;
g[x].pb(y);
g[y].pb(x);
}
clr(mk, 0);
for(int i = 1; i < n; ++i) if(!mk[i]) paint(i, 0);
if(zero) return void(cout << "0\n");
for(pii f : c) unite(f.ft, f.sd);
set<int> v;
for(int i = 1; i < n; ++i) v.insert(get(i));
int ans = 1;
md = 1e9 + 7;
fo(sz(v)) (ans <<= 1) %= md;
cout << ans << endl;
}
int main() {
#ifdef _LOCAL
freopen("in.txt", "r", stdin);
int tests; cin >> tests;
for(int test = 1; test <= tests; ++test) {
cerr << "case #" << test << endl;
solve();
cerr << endl;
}
#else
// freopen("input.txt", "r", stdin); freopen("output.txt", "w", stdout);
ios_base :: sync_with_stdio(0); cin.tie(0); cout.tie(0);
solve();
#endif
return 0;
}
Compilation message
usmjeri.cpp: In function 'int m_bpow(ll, ll)':
usmjeri.cpp:50:26: warning: suggest parentheses around '-' inside '<<' [-Wparentheses]
for(ll p = 1ll << 63 - __builtin_clzll(b); p; p >>= 1) {
~~~^~~~~~~~~~~~~~~~~~~~
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
117 ms |
28024 KB |
Output is correct |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
291 ms |
71928 KB |
Output is correct |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Incorrect |
9 ms |
7936 KB |
Output isn't correct |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Incorrect |
9 ms |
7808 KB |
Output isn't correct |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Incorrect |
12 ms |
8320 KB |
Output isn't correct |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Incorrect |
12 ms |
8448 KB |
Output isn't correct |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Incorrect |
356 ms |
47408 KB |
Output isn't correct |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Incorrect |
400 ms |
51620 KB |
Output isn't correct |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Incorrect |
408 ms |
51496 KB |
Output isn't correct |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Incorrect |
388 ms |
52764 KB |
Output isn't correct |
| 2 |
Halted |
0 ms |
0 KB |
- |
