Submission #635712

#	Time	Username	Problem	Language	Result	Execution time	Memory
635712		IWTIM	Usmjeri (COCI17_usmjeri)	C++14	140 / 140	497 ms	105384 KiB

usmjeri

# include <bits/stdc++.h>
using namespace std;
using ll = long long;
using db = long double; // or double, if TL is tight
using str = string; // yay python! 
 
// pairs
using pii = pair<int,int>;
using pl = pair<ll,ll>;
using pd = pair<db,db>;
#define mp make_pair
#define f first
#define s second
 
#define tcT template<class T
#define tcTU tcT, class U
// ^ lol this makes everything look weird but I'll try it
tcT> using V = vector<T>; 
tcT, size_t SZ> using AR = array<T,SZ>; 
using vi = V<int>;
using vb = V<bool>;
using vl = V<ll>;
using vd = V<db>;
using vs = V<str>;
using vpi = V<pii>;
using vpl = V<pl>;
using vpd = V<pd>;
 
// vectors
// oops size(x), rbegin(x), rend(x) need C++17
#define sz(x) int((x).size())
#define bg(x) begin(x)
#define all(x) bg(x), end(x)
#define rall(x) x.rbegin(), x.rend() 
#define sor(x) sort(all(x)) 
#define rsz resize
#define ins insert 
#define pb push_back
#define eb emplace_back
#define ft front()
#define bk back()
 
#define lb lower_bound
#define ub upper_bound
#define FOR(i,a,b) for (int i = (a); i < (b); ++i)
#define F0R(i,a) FOR(i,0,a)
#define ROF(i,a,b) for (int i = (b)-1; i >= (a); --i)
#define R0F(i,a) ROF(i,0,a)
#define rep(a) F0R(_,a)
#define each(a,x) for (auto& a: x)
const int MOD = 998244353;
const int MX = 2e5+5;
const ll BIG = 1e18; // not too close to LLONG_MAX
const db PI = acos((db)-1);
const int dx[4]{1,0,-1,0}, dy[4]{0,1,0,-1}; // for every grid problem!!
mt19937 rng((uint32_t)chrono::steady_clock::now().time_since_epoch().count()); 
template<class T> using pqg = priority_queue<T,vector<T>,greater<T>>;
struct DSU {
	vi e; void init(int N) { e = vi(N,-1); }
	int get(int x) { return e[x] < 0 ? x : e[x] = get(e[x]); } 
	bool sameSet(int a, int b) { return get(a) == get(b); }
	int size(int x) { return -e[get(x)]; }
	bool unite(int x, int y) { // union by size
		x = get(x), y = get(y); if (x == y) return 0;
		if (e[x] > e[y]) swap(x,y);
		e[x] += e[y]; e[y] = x; return 1;
	}
};
/*
inline namespace Helpers {
	//////////// is_iterable
	// https://stackoverflow.com/questions/13830158/check-if-a-variable-type-is-iterable
	// this gets used only when we can call begin() and end() on that type
	tcT, class = void> struct is_iterable : false_type {};
	tcT> struct is_iterable<T, void_t<decltype(begin(declval<T>())),
	                                  decltype(end(declval<T>()))
	                                 >
	                       > : true_type {};
	tcT> constexpr bool is_iterable_v = is_iterable<T>::value;
 
	//////////// is_readable
	tcT, class = void> struct is_readable : false_type {};
	tcT> struct is_readable<T,
	        typename std::enable_if_t<
	            is_same_v<decltype(cin >> declval<T&>()), istream&>
	        >
	    > : true_type {};
	tcT> constexpr bool is_readable_v = is_readable<T>::value;
 
	//////////// is_printable
	// // https://nafe.es/posts/2020-02-29-is-printable/
	tcT, class = void> struct is_printable : false_type {};
	tcT> struct is_printable<T,
	        typename std::enable_if_t<
	            is_same_v<decltype(cout << declval<T>()), ostream&>
	        >
	    > : true_type {};
	tcT> constexpr bool is_printable_v = is_printable<T>::value;
}*/
using ll = long long;
using db = long double; // or double, if TL is tight
using str = string; // yay python! 
 
// pairs
using pii = pair<int,int>;
using pl = pair<ll,ll>;
using pd = pair<db,db>;
#define mp make_pair
#define f first
#define s second
 
#define tcT template<class T
#define tcTU tcT, class U
// ^ lol this makes everything look weird but I'll try it
tcT> using V = vector<T>; 
tcT, size_t SZ> using AR = array<T,SZ>; 
using vi = V<int>;
using vb = V<bool>;
using vl = V<ll>;
using vd = V<db>;
using vs = V<str>;
using vpi = V<pii>;
using vpl = V<pl>;
using vpd = V<pd>;
 
// vectors
// oops size(x), rbegin(x), rend(x) need C++17
#define sz(x) int((x).size())
#define bg(x) begin(x)
#define all(x) bg(x), end(x)
#define rall(x) x.rbegin(), x.rend() 
#define sor(x) sort(all(x)) 
#define rsz resize
#define ins insert 
#define pb push_back
#define eb emplace_back
#define ft front()
#define bk back()
 
#define lb lower_bound
#define ub upper_bound
#define FOR(i,a,b) for (int i = (a); i < (b); ++i)
#define F0R(i,a) FOR(i,0,a)
#define ROF(i,a,b) for (int i = (b)-1; i >= (a); --i)
#define R0F(i,a) ROF(i,0,a)
#define rep(a) F0R(_,a)
#define each(a,x) for (auto& a: x)
template<class T> using pqg = priority_queue<T,vector<T>,greater<T>>;
 
/*
inline namespace Helpers {
	//////////// is_iterable
	// https://stackoverflow.com/questions/13830158/check-if-a-variable-type-is-iterable
	// this gets used only when we can call begin() and end() on that type
	tcT, class = void> struct is_iterable : false_type {};
	tcT> struct is_iterable<T, void_t<decltype(begin(declval<T>())),
	                                  decltype(end(declval<T>()))
	                                 >
	                       > : true_type {};
	tcT> constexpr bool is_iterable_v = is_iterable<T>::value;
 
	//////////// is_readable
	tcT, class = void> struct is_readable : false_type {};
	tcT> struct is_readable<T,
	        typename std::enable_if_t<
	            is_same_v<decltype(cin >> declval<T&>()), istream&>
	        >
	    > : true_type {};
	tcT> constexpr bool is_readable_v = is_readable<T>::value;
 
	//////////// is_printable
	// // https://nafe.es/posts/2020-02-29-is-printable/
	tcT, class = void> struct is_printable : false_type {};
	tcT> struct is_printable<T,
	        typename std::enable_if_t<
	            is_same_v<decltype(cout << declval<T>()), ostream&>
	        >
	    > : true_type {};
	tcT> constexpr bool is_printable_v = is_printable<T>::value;
}*/
const int N = 3e5 + 5;
int t,n,a[N],b[N],p[N],fix[N],fix1[N],sz[N],m, lv[N];
int x[N],y[N];
vector <int> v[N],con[N],v1[N];
int par[N][20],tin, in[N],out[N],mn[N];
multiset <int> s;
int get_col(int a) {
	if (a == p[a]) return a;
	else return p[a] = get_col(p[a]);
}
void col(int a, int b) {
	a = get_col(a);
	b = get_col(b);
	if (a == b) return ;
	if (sz[a] < sz[b]) swap(a,b);
	p[b] = a;
	sz[a] += sz[b];
	sz[b] = 0; 	
}
void init() {
	for (int i = 1; i <= n; i++) {
		p[i] = i;
		sz[i] = 1;
	}
}
void dfs(int a, int p) {
	lv[a] = lv[p] + 1;
	par[a][0] = p;
	tin++;
	in[a] = tin;
	for (int i = 1; i <= 18; i++) {
		if (par[a][i - 1]) par[a][i] = par[par[a][i - 1]][i - 1];
	}
	for (int to : v[a]) {
		if (to == p) continue;
		dfs(to,a);
	}
	out[a] = tin;
}
int upper(int a, int b) {
	return (in[a] <= in[b] && out[a] >= out[b]);
}
int lca(int a, int b) {
	if (upper(a,b)) return a;
	for (int i = 18; i >= 0; i--) {
		if (par[a][i] && !upper(par[a][i],b)) a = par[a][i];
	}
	return par[a][0];
}
void dfs1(int a, int p) {
	mn[a] = 1e9;
	for (int x : con[a]) mn[a] = min(mn[a], lv[x]);
	for (int to : v[a]) {
		if (to == p) continue;
		dfs1(to,a);
		if (p && mn[to] <= lv[p]) col(a,to);
		mn[a] = min(mn[a], mn[to]);
	}
	
}
void check(int a, int p) {
    fix1[a] = 1;
    for (int to : v1[a]) {
        
        if (to == p) continue;
        if (fix1[to]) {
            cout<<0<<"\n"; exit(0);
        }
        check(to, a);
    }
}
main() {
    std::ios_base::sync_with_stdio(false),cin.tie(0),cout.tie(0);
    cin>>n>>m;
    init();
    for (int i = 1; i <= n - 1; i++) {
    	int a, b;
    	cin>>x[i]>>y[i];
    	v[x[i]].pb(y[i]);
    	v[y[i]].pb(x[i]);
	}
	for (int i = 1; i <= m; i++) {
		cin>>a[i]>>b[i];
	}
	dfs(1,0);
	for (int i = 1; i <= m; i++) {
		int lc = lca(a[i],b[i]);
		if (lv[a[i]] - lv[lc] >= 2) con[a[i]].pb(lc);
		if (lv[b[i]] - lv[lc] >= 2) con[b[i]].pb(lc);
	}
	dfs1(1,0);
	set <pii>ss;
	for (int i = 1; i <= m; i++) {
		int lc = lca(a[i],b[i]); if(lc == a[i] || lc == b[i]) continue;
		int aa = get_col(a[i]); int bb = get_col(b[i]);
		if (ss.count({aa,bb})) continue; 
		ss.insert({aa,bb}); ss.insert({bb,aa});
		v1[aa].pb(bb); v1[bb].pb(aa);
		if (get_col(a[i]) == get_col(b[i])) {
			cout<<0<<"\n";
			exit(0);
		}
	}
	for (int i = 2; i <= n; i++) {
	    if (!fix1[i]) {
	        check(i, 0);
	    }
	}
	for (int i = 1; i <= m; i++) {
	    int lc = lca(a[i],b[i]); if (lc == a[i] || lc == b[i]) continue;
	    col(a[i],b[i]);
	}
	set <int> st;
	for (int i = 2; i <= n; i++) {
		st.insert(get_col(i));
	}
	long long x = 1, mod = 1e9 + 7;
	for (int i = 1; i <= (int)st.size(); i++) {
		x *= 2LL; x %= mod;
	}
	cout<<x<<"\n";
}

Compilation message (stderr)

usmjeri.cpp:252:1: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type]
  252 | main() {
      | ^~~~
usmjeri.cpp: In function 'int main()':
usmjeri.cpp:257:10: warning: unused variable 'a' [-Wunused-variable]
  257 |      int a, b;
      |          ^
usmjeri.cpp:257:13: warning: unused variable 'b' [-Wunused-variable]
  257 |      int a, b;
      |             ^

• Subtask 1: 14 / 14
• Subtask 2: 14 / 14
• Subtask 3: 14 / 14
• Subtask 4: 14 / 14
• Subtask 5: 14 / 14
• Subtask 6: 14 / 14
• Subtask 7: 14 / 14
• Subtask 8: 14 / 14
• Subtask 9: 14 / 14
• Subtask 10: 14 / 14