Submission #1112931

#	Time	Username	Problem	Language	Result	Execution time	Memory
1112931		usukhbaatar	Tropical Garden (IOI11_garden)	C++17	0 / 100	3 ms	592 KiB

garden

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

vector<vector<pair<int, int>>> a;
vector<int> g;
vector<bool> vis;

vector<bool> start;
vector<bool> finish;

int n, m, fn;

void dfs(int u, int p, int i) {
    // cout << p << " -> " << u << endl;
    if (a[u].size() == 0) return;
    int x = (i << 1) + (p > u);
    if (x >= 0 && vis[x]) return;
    vis[x] = 1;
    
    if (i != -1 && u == fn) finish[x] = 1; 
    int id = (a[u].size() == 1 || a[u][0].second != i) ? 0 : 1;
    int v = a[u][id].first;
    int j = a[u][id].second;
    int y = (j << 1) + (v < u);
    if (x != -1) g[x] = y;
    else start[y] = 1;
    // cout << y << " ";
    // cout << x << " to " << y << endl;
    dfs(v, u, j);
}

bool check(int u, int k) {
    for (int i = 0; i < k - 1; i++) {
        u = g[u];
    }
    return finish[u];
}

void count_routes(int N, int M, int P, int ed[][2], int q, int qry[]) {
    n = N, m = (M << 1), fn = P;
    a.resize(n);
    vis.resize(m, 0);
    for (int i = 0; i < n; i++) {
        int u = ed[i][0], v = ed[i][1];
        if (a[u].size() < 2) a[u].push_back({v, i});
        if (a[v].size() < 2) a[v].push_back({u, i});
    }

    // for (int i = 0; i < n; i++) {
    //     cout << i << ": ";
    //     for (int j = 0; j < a[i].size(); j++) {
    //         cout << a[i][j].first << ' ';
    //     }
    //     cout << endl;
    // }

    g.resize(m, -1);
    start.resize(m, 0);
    finish.resize(m, 0);

    for (int i = 0; i < n; i++) {
        dfs(i, m, -1);
    }

    for (int i = 0; i < q; i++) {
        int ans = 0;
        for (int u = 0; u < m; u++) {
            if (start[u] && check(u, qry[i])) ans++;
        }
        answer(ans);
    }

    // for (int i = 0; i < m; i++) {
    //     cout << i << ' ' << g[i] << ' ' << start[i] << ' ' << finish[i] << endl;
    // }
}

• Subtask 1: 0 / 49
• Subtask 2: 0 / 20
• Subtask 3: 0 / 31