Submission #520832

#	Time	Username	Problem	Language	Result	Execution time	Memory
520832		tube5429	Usmjeri (COCI17_usmjeri)	C++14	140 / 140	434 ms	84704 KiB

usmjeri

#include<bits/stdc++.h>
using namespace std;

#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(e,a) for(auto &e : (a))
#define sz(v) (int)(v).size()
#define all(v) (v).begin(),(v).end()
#define rall(v) (v).rbegin(),(v).rend()
#define rsz resize
#define pb push_back
#define f first
#define s second
#define pf push_front
#define ft front()
#define bk back()
#define eb emplace_back
#define lb lower_bound
#define ub upper_bound
#define tcT template<class T
#define tcTU tcT, class U
#define nl "\n"

using ll = long long;
using vi = vector<int>;
using vl = vector<ll>;
using vb = vector<bool>;
using pi = pair<int,int>;
using vpi = vector<pi>;
using str = string;
using vs = vector<str>;
using db = double;
using pl = pair<ll,ll>;
using pd = pair<db,db>;
tcT> using V = vector<T>;
tcT> using pqg = priority_queue<T,vector<T>,greater<T>>;
tcTU> using PR = pair<T,U>;

const int MOD = 1e9+7;
const ll INF = 1e18;
const int dx[] = {-1,0,1,0}, dy[] = {0,-1,0,1};

constexpr int bits(int x) { return x == 0 ? 0 : 31 - __builtin_clz(x); }
constexpr bool onbit(int msk, int i) { return msk>>i&1; }
constexpr ll p2(int x) { return 1LL<<x; }
constexpr int pct(int x) { return __builtin_popcount(x); }
constexpr int lg2(int x) { return x == 0 ? 0 : 31 - __builtin_clz(x); }; //int only

template<int N> constexpr ll pow10 = pow10<N-1> * 10;
template<> constexpr ll pow10<0> = 1;

tcT> bool ckmin(T&a, const T&b) { return b < a ? a = b,1 : 0; }
tcT> bool ckmax(T&a, const T&b) { return b > a ? a = b,1 : 0; }

ll cdiv(ll a, ll b) { return a/b+((a^b)>0&&a%b); }
ll fdiv(ll a, ll b) { return a/b-((a^b)<0&&a%b); } 

tcTU> T fstTrue(T lo, T hi, U f) {
	hi++; assert(lo <= hi);
	while (lo < hi) {
		T mid = lo+(hi-lo)/2;
		f(mid) ? hi = mid : lo = mid+1; 
	} 
	return lo;
}
tcTU> T lstTrue(T lo, T hi, U f) {
	lo--; assert(lo <= hi);
	while (lo < hi) {
		T mid = lo+(hi-lo+1)/2;
		f(mid) ? lo = mid : hi = mid-1;
	} 
	return lo;
}

tcT> void remDup(V<T> &v) {
	sort(all(v)); v.erase(unique(all(v)), end(v)); }
void DBG() { cerr << "]\n"; }
template<class H, class... T> void DBG(H h, T... t) {
	cerr << h; if(sizeof...(t)) cerr << ", ";
	DBG(t...);
}
#ifdef LOCAL
#define dbg(...) cerr << "LINE(" << __LINE__ << ") -> [" << #__VA_ARGS__ << "]: [", DBG(__VA_ARGS__)
#else
#define dbg(...) 0
#endif // LOCAL

void setPrec() { cout << fixed << setprecision(16); }
void setIO(string NAME = "") {
	cin.tie(0)->sync_with_stdio(0);
	setPrec();
	if(sz(NAME)) {
		freopen((NAME + ".in").c_str(),"r",stdin);
		freopen((NAME + ".out").c_str(),"w",stdout);
	}
}

template<int SZ, int LG> struct Tree {
	int N, par[LG][SZ], dep[SZ]; vi adj[SZ];
	void init(int _N) { N = _N; F0R(i,N) adj[i].clear(); }
	void ae(int u, int v) { adj[u].pb(v), adj[v].pb(u); }
	void gen(int R = 0) { dep[par[0][R] = R] = 0; dfs(R); }
	void dfs(int x = 0) {
		FOR(i,1,LG) par[i][x] = par[i-1][par[i-1][x]];
		each(y, adj[x]) if(y!=par[0][x])
			dep[y] = dep[par[0][y] = x] + 1, dfs(y);
	}
	int jmp(int x, int d) {
		F0R(i,LG) if(onbit(d,i)) x = par[i][x];
		return x; 
	}
	int lca(int x, int y) {
		if(dep[x] < dep[y]) swap(x, y);
		x = jmp(x, dep[x] - dep[y]); if(x == y) return x;
		R0F(i,LG) if(par[i][x] != par[i][y]) x = par[i][x], y = par[i][y];
		return par[0][x]; 
	}
	int dist(int x, int y) {
		return dep[x] + dep[y] - (dep[lca(x,y)]<<1);
	}
};

const int MX = 3e5+5;
int N, M, hi[MX], color[MX];
vpi adj[MX];
Tree<MX, lg2(MX)> tr;

int connect(int u) {
	each(v, tr.adj[u]) if(v!=tr.par[0][u]) {
		int tmp = connect(v);
		ckmin(hi[u], tmp);
		if(tmp < tr.dep[u]) {
			adj[u].pb({v,0}); adj[v].pb({u,0});
		}
	}
	return hi[u];
}

bool dfs(int x, int c) {
	if(~color[x]) return color[x] == c;
	color[x] = c;
	each(y, adj[x]) 
		if(!dfs(y.f, c^y.s)) return false;
	
	return true;
}

void solve() {
	cin>>N>>M;
	tr.init(N+5);
	REP(N-1) {
		int u,v; cin>>u>>v, --u, --v;
		tr.ae(u,v);
	}
	tr.gen();
	F0R(i,N) hi[i] = tr.dep[i];
	REP(M) {
		int a,b; cin>>a>>b, --a, --b;
		int c = tr.lca(a,b);
		ckmin(hi[a], tr.dep[c]); ckmin(hi[b], tr.dep[c]);
		if(c!=a && c!=b) {
			adj[a].pb({b,1}); adj[b].pb({a,1});
		}
	}
	connect(0);
	ll ans = 1;
	FOR(i,1,N) if(color[i] == -1) {
		if(!dfs(i, 0)) {
			cout << "0\n";
			return;
		}
		ans = (ans*2)%MOD;
	}
	cout << ans << "\n";
}

int main() {
   	setIO();
	memset(color, -1, sizeof color);

	int t=1;
	//cin>>t;
	while(t-->0) {
		solve();
	}
 
	return 0;
}

Compilation message (stderr)

usmjeri.cpp: In function 'void setIO(std::string)':
usmjeri.cpp:96:10: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   96 |   freopen((NAME + ".in").c_str(),"r",stdin);
      |   ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
usmjeri.cpp:97:10: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   97 |   freopen((NAME + ".out").c_str(),"w",stdout);
      |   ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

• 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