Submission #320177

#	Time	Username	Problem	Language	Result	Execution time	Memory
320177		ant101	Usmjeri (COCI17_usmjeri)	C++14	140 / 140	474 ms	72672 KiB

usmjeri

#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=18;
//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);
        }
    }
    return h[v];
}
int clr[N];
bool is_ok(int v,int p,int colour){
    if(clr[v]!=-1) return clr[v]==colour;
    clr[v]=colour;
//    debug()<<imie(v)<<imie(adj[v]);
    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()
{
//    freopen("in.txt","r",stdin);
    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*binpow(2,M-2,M))%M;
    return 0;
}
/*
5 1
2 3 6 4 1
2 1 4
// 1,2,3,4,2 3,3 4
 
*/

Compilation message (stderr)

usmjeri.cpp: In function 'int lca(int, int)':
usmjeri.cpp:104:5: warning: this 'if' clause does not guard... [-Wmisleading-indentation]
  104 |     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'
  104 |     if(is(a,b)) return a;if(is(b,a)) return 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