Submission #202260

#	Time	Username	Problem	Language	Result	Execution time	Memory
202260		DS007	Cities (BOI16_cities)	C++14	0 / 100	1956 ms	26776 KiB

cities

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

const int N = 1e5;
int n, m, k;
vector<pair<int, long long>> adj[N];
bool is_k[N];
vector<int> k_;

vector<pair<int, long long>> res[N];
auto cmp = [](pair<int, long long> &a, pair<int, long long> &b) {
    return a.second > b.second;
};

void dijkstra(int v) {
    long long dist[n];
    fill(dist, dist + n, 1e15);
    dist[v] = 0;

    priority_queue<pair<int, long long>, vector<pair<int, long long>>, decltype(cmp)> pq(cmp);
    pq.push({v, 0});
    set<int> settled;

    while (settled.size() != n) {
        auto t = pq.top();
        pq.pop();

        if (settled.count(t.first))
            continue;
        settled.insert(t.first);

        for (auto i : adj[t.first]) {
            dist[i.first] = min(dist[i.first], dist[t.first] + i.second);
            pq.push({i.first, dist[i.first]});
        }
    }

    for (int i = 0; i < n; i++) {
        if (i != v && is_k[i])
            res[v].emplace_back(i, dist[i]);
    }
}

long long score() {
    priority_queue<pair<int, long long>, vector<pair<int, long long>>, decltype(cmp)> pq(cmp);
    pq.push({k_[0], 0});

    long long ans = 0;
    set<int> settled;

    while (settled.size() != k) {
        auto t = pq.top();
        pq.pop();

        if (settled.count(t.first))
            continue;
        settled.insert(t.first);
        ans += t.second;

        for (auto i : res[t.first])
            pq.push(i);
    }

    return ans;
}

signed main() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    cout.tie(nullptr);

    cin >> n >> k >> m;
    for (int i = 0; i < k; i++) {
        int v; cin >> v;
        k_.push_back(v - 1);
        is_k[v - 1] = true;
    }

    for (int i = 0; i < m; i++) {
        int a, b, c;
        cin >> a >> b >> c;
        a--, b--;
        adj[a].emplace_back(b, c);
        adj[b].emplace_back(a, c);
    }

    for (int i = 0; i < n; i++) {
        if (is_k[i])
            dijkstra(i);
    }

    cout << score();
}

Compilation message (stderr)

cities.cpp: In function 'void dijkstra(int)':
cities.cpp:24:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     while (settled.size() != n) {
            ~~~~~~~~~~~~~~~^~~~
cities.cpp: In function 'long long int score()':
cities.cpp:51:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     while (settled.size() != k) {
            ~~~~~~~~~~~~~~~^~~~

• Subtask 1: 0 / 22
• Subtask 2: 0 / 14
• Subtask 3: 0 / 15
• Subtask 4: 0 / 23
• Subtask 5: 0 / 26