Submission #1058360

#	Time	Username	Problem	Language	Result	Execution time	Memory
1058360		dozer	Thousands Islands (IOI22_islands)	C++17	22.75 / 100	21 ms	21464 KiB

islands

#include "islands.h"
#include <bits/stdc++.h>
using namespace std;
#define sp " "
#define endl "\n"
#define pii pair<int, int>
#define st first
#define nd second
#define fileio() freopen("input.txt", "r", stdin), freopen("output.txt", "w", stdout)
#define fastio() cin.tie(0), ios_base::sync_with_stdio(0)
#define pb push_back
#define LL node * 2
#define RR node * 2 + 1
#define ll long long
#define MAXN 300005

const int modulo = 1e9 + 7;
const ll INF = 2e18 + 7;

vector<pii> in[MAXN], out[MAXN];

int nxt(int a){
    if (a % 2 == 0) return a + 1;
    return a - 1;
}


int dfs(int node, int par, deque<int> &ans){
    vector<pii> go;
    for (auto i : out[node]){
        if (i.st != par) go.pb(i);
    }

    if (go.size() >= 2){
        int a = go[0].nd, b = go[1].nd;
        ans = {a, nxt(a), b, nxt(b), nxt(a), a, nxt(b), b};
        return 1;
    }
    if (go.empty()) return 0;
    int to = go.front().st;
    int res = dfs(to, node, ans);
    if (res == 0) return 0;
    ans.push_front(go.front().nd);
    ans.push_back(go.front().nd);
    return 1;
}


variant<bool, vector<int>> find_journey(int N, int M, vector<int> U, vector<int> V) {
    for (int i = 0; i < M; i++){
        in[V[i]].pb({U[i], i});
        out[U[i]].pb({V[i], i});
    }

    deque<int> a;
    int res = dfs(0, -1, a);
    if (res == 0) return false;
    vector<int> b;
    for (auto i : a) b.pb(i);
    return b;
}
/*
int main() {
    fileio();
    int N, M;
    assert(2 == scanf("%d %d", &N, &M));

    std::vector<int> U(M), V(M);
    for (int i = 0; i < M; ++i) {
    assert(2 == scanf("%d %d", &U[i], &V[i]));
    }

    std::variant<bool, std::vector<int>> result = find_journey(N, M, U, V);
    if (result.index() == 0) {
    printf("0\n");
    if (std::get<bool>(result)) {
      printf("1\n");
    } else {
      printf("0\n");
    }
    } else {
    printf("1\n");
    std::vector<int> &canoes = std::get<std::vector<int>>(result);
    printf("%d\n", static_cast<int>(canoes.size()));
    for (int i = 0; i < static_cast<int>(canoes.size()); ++i) {
      if (i > 0) {
        printf(" ");
      }
      printf("%d", canoes[i]);
    }
    printf("\n");
    }
    return 0;
}
*/

• Subtask 1: 0 / 5
• Subtask 2: 1.75 / 5
• Subtask 3: 21 / 21
• Subtask 4: 0 / 24
• Subtask 5: 0 / 45