Submission #886731

#	Time	Username	Problem	Language	Result	Execution time	Memory
886731		vjudge1	Usmjeri (COCI17_usmjeri)	C++17	0 / 140	2075 ms	166016 KiB

usmjeri

#include <bits/stdc++.h>
using namespace std;
using i64 = long long;

const int MOD = 1E9 + 7;

const int MAXN = 3E5 + 5;
const int LOG = 25;

int p[LOG][MAXN];
int depth[MAXN];

int get(int a, int b) {
    for(int i = LOG -1; i >= 0; i--) {
        if(b & (1 << i)) {
            a = p[i][a];
        }
    }

    return a;
}

int par[MAXN];
struct DSU {
    int n;
    DSU(int n) : n(n) {
        // 23 orz
        iota(par, par + n, 0);
    }

    int get(int x) {
        if(par[x] == x) {
            return x;
        }

        return par[x] = get(par[x]);
    }

    bool same(int a, int b) {
        return get(a) == get(b);
    }

    bool unite(int u, int v) {
        if(same(u, v)) {
            return false;
        }

        u = get(u); 
        v = get(v);

        par[u] = v;

        return true;
    }
};

int lca(int a, int b) {
    if(depth[a] > depth[b]) {
        swap(a, b);
    }

    b = get(b, depth[b] - depth[a]);
    if(a == b) {
        return a;
    }

    for(int lg = LOG -1; lg >= 0; lg--) {
        if(p[lg][a] != p[lg][b]) {
            a = p[lg][a];
            b = p[lg][b];
        }
    }

    return p[0][a];
}

#define ONLINE_JUDGE
void solve() {
    int n, m;
    cin >> n >> m;

    vector <int> adj[n +1];
    for(int i = 1; i <= n -1; i++) {
        int u, v;
        cin >> u >> v;

        adj[u].emplace_back(v);
        adj[v].emplace_back(u);
    }

    function <void(int, int)> dfs = [&](int node, int par) -> void {
        p[0][node] = par;
        depth[node] = depth[par] +1;
        for(int &child : adj[node]) {
            if(child != par) {
                dfs(child, node);
            }
        }
    };

    dfs(1, 0);

    for(int lg = 1; lg < LOG; lg++) {
        for(int i = 1; i <= n; i++) {
            p[lg][i] = p[lg -1][p[lg -1][i]];
        }
    }

    map <pair <int, int>, int> mp;
    DSU dsu(n +1);
    function <void(int, int, int)> dfsP = [&](int a, int b, int ty) -> void {
        while(a != b) {
            dsu.unite(a, p[0][a]);
            mp[{a, b}] |= ty;
            a = p[0][a];
        }
    };

    for(int i = 1; i <= m; i++) {
        int a, b;
        cin >> a >> b;

        if(depth[a] < depth[b]) {
            swap(a, b);
        } else if(depth[a] == depth[b]) {
            if(a < b) {
                swap(a, b);
            }
        }

        int c = lca(a, b);
        dfsP(a, c, 1);
        dfsP(b, c, 2);
    }

    for(auto &[x, y] : mp) {
        if(y == 3) {
            cout << 0;
            return;
        }
    }

    int ans = 1;
    for(int i = 1; i <= n; i++) {
        if(dsu.get(i) == i) {
            ans = (ans * 2) % MOD;
        }
    }

    cout << ans;
    
    return;
}

signed main() {
    #ifndef ONLINE_JUDGE
        freopen("in.txt", "r", stdin);
        freopen("out.txt", "w", stdout);
    #endif

    ios_base::sync_with_stdio(false);
    cin.tie(NULL); cout.tie(NULL);

    int t = 1; //cin >> t;
    for(int i = 1; i <= t; i++) {
        solve();
    }

    return 0;
}

• Subtask 1: 0 / 14
• Subtask 2: 0 / 14
• Subtask 3: 0 / 14
• Subtask 4: 0 / 14
• Subtask 5: 0 / 14
• Subtask 6: 0 / 14
• Subtask 7: 0 / 14
• Subtask 8: 0 / 14
• Subtask 9: 0 / 14
• Subtask 10: 0 / 14