Submission #995121

#	Time	Username	Problem	Language	Result	Execution time	Memory
995121		Szil	Jail (JOI22_jail)	C++17	100 / 100	828 ms	179652 KiB

jail

#include <bits/stdc++.h>

using namespace std;
using ll = long long;

const int MAXN = 200'100;

vector<int> g[MAXN], g2[MAXN*21];
int pos[MAXN], tin[MAXN], tout[MAXN], head[MAXN], heavy[MAXN], sz[MAXN], par[MAXN], 
    s[MAXN], e[MAXN], depth[MAXN], col[MAXN*21], timer, pos_timer, n, m;
bool ok;

void init() {
    for (int i = 1; i <= n; i++) {
        g[i].clear();
    }
    for (int i = 1; i <= 20*n; i++) {
        g2[i].clear();
    }
    fill(heavy, heavy+n+1, 0);
    fill(s, s+n+1, 0);
    fill(e, e+n+1, 0);
    fill(col, col+20*n+1, 0);
    timer = pos_timer = 1;
    ok = true;
}

int get_segtree1_index(int u) {
    return 10*n + u;
}

int get_segtree2_index(int u) {
    return n + u;
}

int get_path_index(int u) {
    return u;
}

void dfs(int u, int p = -1, int d = 0) {
    tin[u] = timer++;
    sz[u] = 1;
    depth[u] = d;
    for (int v : g[u]) {
        if (v == p) continue;
        par[v] = u;
        dfs(v, u, d+1);
        sz[u] += sz[v];
        if (sz[heavy[u]] < sz[v]) {
            heavy[u] = v;
        }
    }
    tout[u] = timer++;
}

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

int nxt(int u, int v) {
    if (u == v) return -1;
    if (is_ancestor(u, v)) {
        for (int x : g[u]) {
            if (x != par[u] && is_ancestor(x, v)) return x;
        }
    } else {
        return par[u];
    }
}

void dfs2(int u, int h, int p) {
    head[u] = h;
    pos[u] = pos_timer++;
    if (heavy[u]) {
        dfs2(heavy[u], h, u);
    }
    for (int v : g[u]) {
        if (v == p || v == heavy[u]) continue;
        dfs2(v, v, u);
    }
}

void dfs3(int u) {
    col[u] = 1;
    for (int v : g2[u]) {
        if (col[v] == 0) dfs3(v);
        else if (col[v] == 1) ok = false;
    }
    col[u] = 2;
}

void build_segtree1(int v, int tl, int tr) {
    if (tl == tr) {
        if (s[tl]) {
            g2[get_segtree1_index(v)].emplace_back(get_path_index(s[tl]));
        }
    } else {
        int tm = (tl + tr) / 2;
        build_segtree1(2*v, tl, tm);
        build_segtree1(2*v+1, tm+1, tr);
        g2[get_segtree1_index(v)].emplace_back(get_segtree1_index(2*v));
        g2[get_segtree1_index(v)].emplace_back(get_segtree1_index(2*v+1));
    }
}

void build_segtree2(int v, int tl, int tr) {
    if (tl == tr) {
        if (e[tl]) {
            g2[get_path_index(e[tl])].emplace_back(get_segtree2_index(v));
        }
    } else {
        int tm = (tl + tr) / 2;
        build_segtree2(2*v, tl, tm);
        build_segtree2(2*v+1, tm+1, tr);
        g2[get_segtree2_index(2*v)].emplace_back(get_segtree2_index(v));
        g2[get_segtree2_index(2*v+1)].emplace_back(get_segtree2_index(v));
    }
}

void add_segtree1_edge(int v, int tl, int tr, int l, int r, int node) {
    if (l > r) return;
    if (l == tl && r == tr) {
        g2[node].emplace_back(get_segtree1_index(v));
    } else {
        int tm = (tl + tr) / 2;
        add_segtree1_edge(2*v, tl, tm, l, min(tm, r), node);
        add_segtree1_edge(2*v+1, tm+1, tr, max(tm+1, l), r, node);
    }
}

void add_segtree2_edge(int v, int tl, int tr, int l, int r, int node) {
    if (l > r) return;
    if (l == tl && r == tr) {
        g2[get_segtree2_index(v)].emplace_back(node);
    } else {
        int tm = (tl + tr) / 2;
        add_segtree2_edge(2*v, tl, tm, l, min(tm, r), node);
        add_segtree2_edge(2*v+1, tm+1, tr, max(tm+1, l), r, node);
    }
}

void qry1(int u, int v, int node) {
    while (head[u] != head[v]) {
        if (depth[head[u]] < depth[head[v]]) swap(u, v);
        add_segtree1_edge(1, 1, n, pos[head[u]], pos[u], node);
        u = par[head[u]];
    }
    if (depth[u] > depth[v]) swap(u, v);
    add_segtree1_edge(1, 1, n, pos[u], pos[v], node);
}

void qry2(int u, int v, int node) {
    while (head[u] != head[v]) {
        if (depth[head[u]] < depth[head[v]]) swap(u, v);
        add_segtree2_edge(1, 1, n, pos[head[u]], pos[u], node);
        u = par[head[u]];
    }
    if (depth[u] > depth[v]) swap(u, v);
    add_segtree2_edge(1, 1, n, pos[u], pos[v], node);
}

void solve() {
    init();
    cin >> n;
    for (int i = 0; i < n-1; i++) {
        int u, v; cin >> u >> v;
        g[u].emplace_back(v);
        g[v].emplace_back(u);
    } 
    cin >> m;
    vector<pair<int, int>> edges(m+1);
    dfs(1);
    dfs2(1, 1, -1);
    for (int i = 1; i <= m; i++) {
        cin >> edges[i].first >> edges[i].second;
        auto [u, v] = edges[i];
        s[pos[u]] = i;
        e[pos[v]] = i;
    }
    build_segtree1(1, 1, n);
    build_segtree2(1, 1, n);
    for (int i = 1; i <= m; i++) {
        auto [u, v] = edges[i];
        qry1(nxt(u, v), v, get_path_index(i));
        qry2(u, nxt(v, u), get_path_index(i));
    }
    for (int i = 1; i <= m; i++) {
        int u = get_path_index(i);
        if (col[u] == 0) dfs3(u);
    }
    cout << (ok?"Yes\n":"No\n");
}

int main() {
    ios::sync_with_stdio(0); cin.tie(0);
    int t; cin >> t;
    while (t--) {
        solve();
    }
}

Compilation message (stderr)

jail.cpp: In function 'int nxt(int, int)':
jail.cpp:69:1: warning: control reaches end of non-void function [-Wreturn-type]
   69 | }
      | ^

• Subtask 1: 5 / 5
• Subtask 2: 5 / 5
• Subtask 3: 16 / 16
• Subtask 4: 28 / 28
• Subtask 5: 12 / 12
• Subtask 6: 11 / 11
• Subtask 7: 23 / 23