Submission #308652

#	Time	Username	Problem	Language	Result	Execution time	Memory
308652		lacito	Stations (IOI20_stations)	C++14	0 / 100	921 ms	1024 KiB

stations

#include "stations.h"
#include <algorithm>
#include <vector>

using namespace std;

vector<vector<int>> g;
vector<int> intime, outtime, depth;
int time;

void dfs(int v) {
    intime[v] = time++;
    for (int x : g[v])
        if (intime[x] == -1) {
            depth[x] = depth[v] + 1;
            dfs(x);
        }
    outtime[v] = time++;
}

vector<int> label(int n, int k, vector<int> u, vector<int> v) {
	g.assign(n, {});
	intime.assign(n, -1);
	outtime.assign(n, -1);
	depth.assign(n, 0);
	for (int i = 0; i < n - 1; i++) {
        g[u[i]].push_back(v[i]);
        g[v[i]].push_back(u[i]);
	}
	time = 0;
	dfs(0);
	vector<int> labels(n);
	for (int i = 0; i < n; i++) {
		labels[i] = depth[i] % 2 == 0 ? intime[i] / 2 : outtime[i] / 2;
	}
	return labels;
}

int find_next_station(int s, int t, vector<int> c) {
    // sort(c.begin(), c.end()); they are already sorted
    if (s < c[0]) {
        // s: intime, c[i]: outtime, c.back(): parent of s
        // subtree of s: s < t <= c[c.size() - 2]
        if (t < s || c.size() == 1 || t > c[c.size() - 2])
            return c.back();
        return *(upper_bound(c.begin(), c.end(), t) - 1);
    } else {
        // s: outtime, c[i]: intime, c[0]: parent of s
        // subtree of s: c[1] <= t < s
        if (t > s || c.size() == 1 || t < c[1])
            return c[0];
        return *lower_bound(c.begin(), c.end(), t);
    }
}

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