Submission #235189

#	Time	Username	Problem	Language	Result	Execution time	Memory
235189		ne4eHbKa	Usmjeri (COCI17_usmjeri)	C++17	140 / 140	477 ms	72208 KiB

usmjeri

//{ <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; col[v] = c;
    for(int u : g[v]) paint(u, 1 - 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;
    if(get(pr[v]) == get(v)) {
        find(pr[v]);
        pr[v] = pr[pr[v]];
    }
}

void path(int u, int v) {
    find(v);
    while(h[u] < h[pr[v]]) {
        unite(v, pr[v]);
        find(v = pr[v]);
    }
}

//void path(int u, int v) {
//    for(; p[v][0] != u; v = p[v][0])
//        unite(v, p[v][0]);
//}

void solve() {
    timer = 0;
    fo(n) g[i].clear();
    clr(mk, 0);

    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);
        }
    }

    #define no return void(cout << "0\n")

    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) no;
        g[x].pb(y);
        g[y].pb(x);
    }

    zero = false;
    for(int i = 1; i < n; ++i) if(!mk[i]) paint(i, 0);
    if(zero) no;

    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 (stderr)

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) {
                       ~~~^~~~~~~~~~~~~~~~~~~~

• 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