Submission #1058450

#	Time	Username	Problem	Language	Result	Execution time	Memory
1058450		dozer	Thousands Islands (IOI22_islands)	C++17	24 / 100	29 ms	22632 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 vis[MAXN], done[MAXN];

int dfs(int node, deque<int> &ans, stack<pii> edges){
    done[node] = 1;
    vis[node] = 1;

    for (auto i : out[node]){
        if (done[i.st]){
            vector<int> tmp;
            while(true){
                int t = edges.top().st;
                tmp.pb(edges.top().nd);
                edges.pop();
                if (t == i.st) break;
                if (edges.empty()) break;
            }
            reverse(tmp.begin(), tmp.end());
            tmp.pb(i.nd);
            ans.clear();
            for (auto j : tmp) ans.pb(j);
            for (auto j : tmp) ans.pb(j + 1);
            reverse(tmp.begin(), tmp.end());
            for (auto j : tmp) ans.pb(j);
            for (auto j : tmp) ans.pb(j + 1);

            while(!edges.empty()){
                int t = edges.top().nd;
                edges.pop();
                ans.push_front(t);
                ans.pb(t);
            }
            return 1;
        }
        else if (vis[i.st]) continue;
        else{
            edges.push({node, i.nd});
            int res = dfs(i.st, ans, edges);
            if (res == 1) return 1;
            edges.pop();
        }
    }

    done[node] = 0;
    return 0;
}


variant<bool, vector<int>> find_journey(int N, int M, vector<int> U, vector<int> V) {
    for (int i = 0; i < M; i += 2){
        in[V[i]].pb({U[i], i});
        out[U[i]].pb({V[i], i});
    }

    deque<int> a;
    stack<pii> tmp;
    int res = dfs(0, a, tmp);
    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: 0 / 5
• Subtask 3: 0 / 21
• Subtask 4: 24 / 24
• Subtask 5: 0 / 45