Submission #714931

#	Time	Username	Problem	Language	Result	Execution time	Memory
714931		stevancv	Inside information (BOI21_servers)	C++14	50 / 100	374 ms	39040 KiB

servers

#include <bits/stdc++.h>
#define ll long long
#define ld long double
#define sp ' '
#define en '\n'
#define smin(a, b) a = min(a, b)
#define smax(a, b) a = max(a, b)
using namespace std;
const int N = 120000 + 2;
const int inf = 1e9;
vector<array<int, 2>> g[N];
int par[N][17], in[N], out[N], val[N], donji[N], dep[N], tsz;
bool inc[N][17], dek[N][17];
void Dfs(int s, int e) {
    in[s] = ++tsz;
    par[s][0] = e;
    inc[s][0] = 1;
    dek[s][0] = 1;
    for (int i = 1; i < 17; i++) {
        int u = par[s][i - 1];
        par[s][i] = par[u][i - 1];
        inc[s][i] = inc[s][i - 1] & inc[u][i - 1] & (donji[u] < val[u]);
        dek[s][i] = dek[s][i - 1] & dek[u][i - 1] & (donji[u] > val[u]);
    }
    for (auto zz : g[s]) {
        int u = zz[0]; int i = zz[1];
        if (u == e) continue;
        dep[u] = dep[s] + 1;
        donji[s] = i;
        val[u] = i;
        Dfs(u, s);
    }
    out[s] = tsz;
}
bool Ancestor(int u, int v) {
    return in[u] <= in[v] && out[v] <= out[u];
}
int Lca(int u, int v) {
    if (Ancestor(u, v)) return u;
    if (Ancestor(v, u)) return v;
    for (int i = 16; i >= 0; i--) {
        if (par[u][i] && !Ancestor(par[u][i], v)) u = par[u][i];
    }
    return par[u][0];
}
int Kth(int u, int k) {
    for (int i = 16; i >= 0; i--) {
        if ((1 << i) & k) u = par[u][i];
    }
    return u;
}
bool MozeI(int u, int v) {
    if (u == v) return 1;
    int r = dep[u] - dep[v];
    bool ans = 1;
    for (int i = 16; i >= 0 && ans; i--) {
        if ((1 << i) & r) {
            ans &= inc[u][i];
            r -= (1 << i);
            if (r != 0) ans &= (val[Kth(u, (1 << i) - 1)] < val[par[u][i]]);
            u = par[u][i];
        }
    }
    return ans;
}
bool MozeD(int u, int v) {
    if (u == v) return 1;
    int r = dep[u] - dep[v];
    bool ans = 1;
    for (int i = 16; i >= 0 && ans; i--) {
        if ((1 << i) & r) {
            ans &= dek[u][i];
            r -= (1 << i);
            if (r != 0) ans &= (val[Kth(u, (1 << i) - 1)] > val[par[u][i]]);
            u = par[u][i];
        }
    }
    return ans;
}
int main() {
    ios::sync_with_stdio(false);
    cin.tie(0);
    cout.tie(0);
    int n, k;
    cin >> n >> k;
    vector<array<int, 3>> all;
    int cnt = 0;
    for (int i = 0; i < n + k - 1; i++) {
        char ch; cin >> ch;
        int u, v;
        if (ch == 'C') {
            cin >> u;
            continue;
        }
        cin >> u >> v;
        if (ch == 'S') {
            g[u].push_back({v, cnt});
            g[v].push_back({u, cnt});
            all.push_back({0, u, v});
            cnt += 1;
        }
        else all.push_back({1, u, v});
    }
    Dfs(1, 0);
    cnt = 0;
    for (int i = 0; i < all.size(); i++) {
        if (all[i][0] == 0) {
            cnt += 1;
            continue;
        }
        int u = all[i][1]; int v = all[i][2];
        swap(u, v);
        if (u == v) {
            cout << "yes" << en;
            continue;
        }
        int lca = Lca(u, v);
        int uu, vv; uu = vv = -1;
        if (u != lca) uu = val[Kth(u, dep[u] - dep[lca] - 1)];
        if (v != lca) vv = val[Kth(v, dep[v] - dep[lca] - 1)];
        bool ans = MozeI(u, lca) & MozeD(v, lca);
        if (uu != -1 && vv != -1) ans &= uu < vv;
        int lst = val[v];
        if (v == lca) lst = uu;
        ans &= lst < cnt;
        if (ans) cout << "yes" << en;
        else cout << "no" << en;
    }
    return 0;
}

Compilation message (stderr)

servers.cpp: In function 'int main()':
servers.cpp:106:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::array<int, 3> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  106 |     for (int i = 0; i < all.size(); i++) {
      |                     ~~^~~~~~~~~~~~

• 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