Submission #1065691

#	Time	Username	Problem	Language	Result	Execution time	Memory
1065691		mispertion	Inside information (BOI21_servers)	C++17	50 / 100	197 ms	68692 KiB

servers

#include <bits/stdc++.h>

using namespace std;
#pragma GCC optimize("Ofast")

mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
typedef long long ll;
#define int ll
typedef unsigned long long ull;
typedef long double ld;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;

#define pb push_back
#define all(x) x.begin(), x.end()
#define sz(x) (int)x.size()
#define mispertion ios_base::sync_with_stdio(0), cin.tie(0), cout.tie(0)
#define F first
#define S second
#define getlast(s) (*s.rbegin())
#define debg cout << "OK\n"

const ld PI = 3.1415926535;
const int N = 3e5 + 10;
const int M = 1e5 + 10;
int mod = 998244353;
const int infi = INT_MAX;
const ll infl = 1e16;
const int P = 2;

int mult(int a, int b){
    return a * 1LL * b % mod;
}

int sum(int a, int b){
    if(a + b >= mod)
        return a + b - mod;
    if(a + b < 0)
        return a + b + mod;
    return a + b;
}

int binpow(int a, int n){
    if (n == 0)
        return 1;
    if (n % 2 == 1){
        return mult(binpow(a, n - 1), a);
    }
    else{
        auto b = binpow(a, n / 2);
        return mult(b, b);
    }
}

const int K = 21;

int n, q, up[N][K], tin[N], tout[N], tick, d[N], edg[N];
vector<int> g[N];
pair<char, pii> qs[N];

struct dsu{
    int p[N], sz[N];
    pii mnd[N];

    dsu(int n){
        for(int i = 1; i <= n; i++){
            p[i] = i;
            sz[i] = 1;
            mnd[i] = {d[i], i};
        }
    }

    int getp(int v){
        if(p[v] == v)
            return v;
        return p[v] = getp(p[v]);
    }

    void uni(int a, int b){
        a = getp(a);
        b = getp(b);
        if(a == b)
            return;
        if(sz[a] > sz[b])
            swap(a, b);
        p[a] = b;
        sz[b] += sz[a];
        mnd[b] = min(mnd[b], mnd[a]);
    }
};

void dfs(int v, int p){
    tin[v] = ++tick;
    up[v][0] = p;
    for(int k = 1; k < K; k++)
        up[v][k] = up[up[v][k - 1]][k - 1];
    for(auto u : g[v]){
        if(u == p) continue;
        d[u] = d[v] + 1;
        dfs(u, v);
    }
    tout[v] = tick;
}

bool isasc(int p, int v){
    return (tin[p] <= tin[v] && tout[v] <= tout[p]);
}

int prlca(int v, int u){
    for(int k = K - 1; k >= 0; k--){
        if(!isasc(up[v][k], u))
            v = up[v][k];
    }
    return v;
}

void solve(){
    //freopen("in.txt", "r", stdin);
    cin >> n >> q;
    for(int i = 1; i <= n + q - 1; i++){
        char tp;
        cin >> tp;
        int a, b;
        if(tp == 'S'){
            cin >> a >> b;
            g[a].pb(b);
            g[b].pb(a);
        }else if(tp == 'Q'){
            cin >> a >> b;
        }else{
            cin >> a;
        }
        qs[i] = {tp, {a, b}};
    }
    dfs(1, 1);
    dsu inc = dsu(n);
    dsu dec = dsu(n);
    int cur = 0;
    for(int i = 1; i <= n + q - 1; i++){
        if(qs[i].F == 'S'){
            int u = qs[i].S.F, v = qs[i].S.S;
            if(up[v][0] != u)
                swap(u, v);
            edg[v] = ++cur;
            for(auto to : g[v]){
                if(to == u) continue;
                if(edg[to]){
                    inc.uni(v, to);
                }
            }
            if(edg[u])
                dec.uni(v, u);
        }else if(qs[i].F == 'Q'){
            int fr = qs[i].S.S, to = qs[i].S.F;
            if(isasc(fr, to)){
                int v = dec.mnd[dec.getp(to)].S;
                if(isasc(v, fr)){
                    cout << "yes\n";
                    continue;
                }
                if(up[v][0] != fr){
                    cout << "no\n";
                    continue;
                }
                if(edg[v]){
                    cout << "yes\n";
                }else{
                    cout << "no\n";
                }
            }else if(isasc(to, fr)){
                int v = inc.mnd[inc.getp(fr)].S;
                if(isasc(v, to)){
                    cout << "yes\n";
                    continue;
                }
                if(up[v][0] != to){
                    cout << "no\n";
                    continue;
                }
                if(edg[v]){
                    cout << "yes\n";
                }else{
                    cout << "no\n";
                }
            }else{
                int ufr = inc.mnd[inc.getp(fr)].S;
                int uto = dec.mnd[dec.getp(to)].S;
                int lfr = prlca(fr, to);
                int lto = prlca(to, fr);
                if(!isasc(ufr, lfr) || !isasc(uto, lto)){
                    cout << "no\n";
                    continue;
                } 
                if(edg[lfr] && edg[lto] && edg[lfr] < edg[lto]){
                    cout << "yes\n";
                }else{
                    cout << "no\n";
                }
            }
        }else{
            cout << 0 << '\n';
        }
    }
}

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

• Subtask 1: 2.5 / 2.5
• Subtask 2: 0 / 2.5
• Subtask 3: 2.5 / 2.5
• Subtask 4: 0 / 2.5
• Subtask 5: 5 / 5
• Subtask 6: 0 / 5
• Subtask 7: 10 / 10
• Subtask 8: 0 / 10
• Subtask 9: 12.5 / 12.5
• Subtask 10: 0 / 12.5
• Subtask 11: 17.5 / 17.5
• Subtask 12: 0 / 17.5