Submission #956378

#	Time	Username	Problem	Language	Result	Execution time	Memory
956378		Desh03	Stations (IOI20_stations)	C++17	0 / 100	560 ms	15196 KiB

stations

#include <bits/stdc++.h>

using namespace std;

const int lg = 20, N = 100000;
vector<int> g[N];
int up[lg][N], in[N], en[N], dep[N], t;

void dfs(int u) {
    for (int v : g[u]) {
        g[v].erase(find(g[v].begin(), g[v].end(), u));
        in[v] = t++;
        up[0][in[v]] = in[u];
        for (int i = 1; i < lg; i++) {
            up[i][in[v]] = up[i - 1][up[i - 1][in[v]]];
        }
        dep[in[v]] = dep[in[u]] + 1;
        dfs(v);
    }
    en[in[u]] = t;
}

bool upper(int u, int v) {
    return u <= v && en[v] <= en[u];
}

vector<int> label(int n, int k, vector<int> u, vector<int> v) {
    for (int i = 0; i < n; i++) g[i].clear();
    for (int i = 0; i < n - 1; i++) {
        g[u[i]].push_back(v[i]);
        g[v[i]].push_back(u[i]);
    }
    in[0] = t++;
    dep[in[0]] = 0;
    for (int i = 0; i < lg; i++) {
        up[i][in[0]] = in[0];
    }
    dfs(0);
    vector<int> ret(n);
    for (int i = 0; i < n; i++) {
        ret[i] = in[i];
    }
    return ret;
}

int kth(int u, int k) {
    for (int i = 0; i < lg; i++) {
        if (k >> i & 1) {
            u = up[i][u];
        }
    }
    return u;
}

int find_next_station(int s, int t, vector<int> c) {
    if (!upper(s, t)) return up[0][s];
    return kth(t, dep[t] - dep[s] - 1);
}

• Subtask 1: 0 / 5
• Subtask 2: 0 / 8
• Subtask 3: 0 / 16
• Subtask 4: 0 / 10
• Subtask 5: 0 / 61