Submission #517207

#	Time	Username	Problem	Language	Result	Execution time	Memory
517207		Ai7081	Stations (IOI20_stations)	C++17	100 / 100	1004 ms	928 KiB

stations

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

int cnt;
vector<int> ret, sub;
vector<vector<int>> adj;

void dfs(int v, int p, bool ismax) {
    ret[v] = cnt;
    sub[v] = 1;
    cnt += (!ismax);
    for (auto to : adj[v]) {
        if (to == p) continue;
        dfs(to, v, !ismax);
        if (ismax) ret[v] += sub[to];
        sub[v] += sub[to];
    }
    cnt += ismax;
    return;
}

vector<int> label(int n, int k, vector<int> u, vector<int> v) {
    adj.assign(n, vector<int>());
    for (int i=0; i<n-1; i++) {
        adj[u[i]].push_back(v[i]);
        adj[v[i]].push_back(u[i]);
    }
    sub.assign(n, 0);
    ret.assign(n, 0);
    cnt = 0;
    dfs(0, 0, 0);
    return ret;
}

int find_next_station(int s, int t, vector<int> c) {
    bool ismax = (s > c[0]);
    if (ismax) {
        if (t > s) return c[0];
        for (int i=1; i<(int)c.size(); i++) {
            if (t < c[i]) return c[i-1];
        }
        return c[c.size()-1];
    }
    else {
        if (t < s) return c[c.size()-1];
        for (int i=c.size()-2; i>=0; i--) {
            if (t > c[i]) return c[i+1];
        }
        //cout << "test " << c[0] << endl;
        return c[0];
    }
}

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