Submission #753879

#	Time	Username	Problem	Language	Result	Execution time	Memory
753879		jakobrs	Stranded Far From Home (BOI22_island)	C++17	20 / 100	253 ms	25832 KiB

island

#include <iostream>
#include <queue>
#include <tuple>
#include <utility>
#include <vector>

using i64 = int64_t;

int main() {
    std::cin.tie(nullptr)->sync_with_stdio(false);

    i64 n, m;
    std::cin >> n >> m;

    std::vector<i64> a(n);
    for (i64 i = 0; i < n; i++) std::cin >> a[i];

    std::vector<std::vector<i64>> adj(n);
    std::vector<std::vector<i64>> children(n);
    for (i64 i = 0; i < m; i++) {
        i64 u, v;
        std::cin >> u >> v;
        u--, v--;

        adj[u].push_back(v);
        adj[v].push_back(u);

        children[std::min(u, v)].push_back(std::max(u, v));
    }

    if (n <= 2000 && m <= 2000) {
        std::string result;
        result.reserve(n);

        std::vector<i64> visited(n);
        for (i64 i = 0; i < n; i++) {
            struct Node {
                i64 size;
                i64 idx;

                bool operator<(const Node &rhs) const {
                    return std::tie(rhs.size, idx) < std::tie(size, rhs.idx);
                }
            };

            std::priority_queue<Node> q;
            std::fill(visited.begin(), visited.end(), false);
            visited[i] = true;

            i64 mass = a[i];
            q.push(Node{.size = 0, .idx = i});

            while (!q.empty()) {
                Node node = q.top();
                if (node.size > mass) break;
                mass += node.size;

                q.pop();
                for (i64 j : adj[node.idx]) {
                    if (!visited[j]) {
                        visited[j] = true;
                        q.push(Node{.size = a[j], .idx = j});
                    }
                }
            }

            result.push_back(q.empty() ? '1' : '0');
        }

        std::cout << result;
    } else {
        std::string result(n, '0');

        std::vector<i64> sizes(n);
        for (i64 i = n - 1; i >= 0; i--) {
            sizes[i] = a[i];

            for (i64 j : children[i]) {
                sizes[i] += sizes[j];
            }
        }

        result[0] = '1';

        for (i64 i = 0; i < n; i++) {
            if (result[i] == '1') {
                for (i64 j : children[i]) {
                    if (sizes[j] >= a[i]) {
                        result[j] = '1';
                    }
                }
            }
        }

        std::cout << result;
    }
}

• Subtask 1: 10 / 10
• Subtask 2: 10 / 10
• Subtask 3: 0 / 15
• Subtask 4: 0 / 30
• Subtask 5: 0 / 35