Submission #1324114

#	Time	Username	Problem	Language	Result	Execution time	Memory
1324114		sh_qaxxorov_571	Stations (IOI20_stations)	C++20	0 / 100	393 ms	564 KiB

stations

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

using namespace std;

// Qo'shnichilik ro'yxati va tartib raqamlari uchun o'zgaruvchilar
vector<vector<int>> adj;
vector<int> labels;
int timer;

// DFS orqali Pre-order va Post-order raqamlash
void dfs(int u, int p, int depth) {
    int pre = timer++;
    for (int v : adj[u]) {
        if (v != p) {
            dfs(v, u, depth + 1);
        }
    }
    int post = timer++;
    
    // Juft chuqurlikda Pre-order, toq chuqurlikda Post-order yorlig'ini beramiz
    if (depth % 2 == 0) {
        labels[u] = pre;
    } else {
        labels[u] = post;
    }
}

// 1. Stansiyalarga yorliq berish funksiyasi
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]);
    }
    
    labels.resize(n);
    timer = 0;
    dfs(0, -1, 0);
    
    // Yorliqlarni 0 dan n-1 gacha bo'lgan oraliqqa siqish (label uniqueness)
    vector<int> sorted_labels = labels;
    sort(sorted_labels.begin(), sorted_labels.end());
    for (int i = 0; i < n; i++) {
        labels[i] = lower_bound(sorted_labels.begin(), sorted_labels.end(), labels[i]) - sorted_labels.begin();
    }
    
    return labels;
}

// 2. Keyingi stansiyani topish funksiyasi
int find_next_station(int s, int t, vector<int> c) {
    // s - hozirgi tugun, t - maqsad, c - qo'shnilar
    
    // Agar s < c[0] bo'lsa, demak s tugunida Pre-order yorlig'i bor (juft qatlam)
    if (s < c[0]) {
        // Maqsad ostki daraxtda ekanligini tekshiramiz
        for (int i = 0; i < (int)c.size() - 1; i++) {
            int left = c[i];
            int right = c[i + 1] - 1;
            if (t >= left && t <= right) return c[i];
        }
        // Agar ostki daraxtda bo'lmasa, ota tugunga (oxirgi qo'shni) yuboramiz
        return c.back();
    } 
    // Aks holda, s tugunida Post-order yorlig'i bor (toq qatlam)
    else {
        // Post-order holati uchun teskari tekshiruv
        for (int i = (int)c.size() - 1; i > 0; i--) {
            int right = c[i];
            int left = c[i - 1] + 1;
            if (t >= left && t <= right) return c[i];
        }
        // Agar ostki daraxtda bo'lmasa, ota tugunga (birinchi qo'shni) yuboramiz
        return c[0];
    }
}

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