Submission #391047

#	Time	Username	Problem	Language	Result	Execution time	Memory
391047		Victor	Toll (BOI17_toll)	C++17	25 / 100	3057 ms	6724 KiB

toll

#include <bits/stdc++.h>

using namespace std;

#define rep(i, a, b) for (int i = a; i < (b); ++i)
#define per(i, a, b) for (int i = b - 1; i >= (a); --i)
#define trav(a, x) for (auto &a : x)

#define all(x) x.begin(), x.end()
#define sz(x) x.size()
#define pb push_back

#define umap unordered_map
#define uset unordered_set

typedef pair<int, int> ii;
typedef pair<int, ii> iii;
typedef vector<int> vi;
typedef vector<ii> vii;
typedef vector<vi> vvi;
typedef long long ll;

const int INF = 1000000007;

vii graph[50001];
int n, rgt[50001], dist[50001];

void solve(int u, int d) {
    if (n <= u) return;

    dist[u] = d;
    if (graph[u].empty()) {
        rgt[u] = u;
        solve(u + 1, 0);

    } else {
        int v, w;
        tie(v, w) = graph[u][0];
        solve(v,d+w);
        rgt[u] = rgt[v];
    }
}

int main() {
    cin.tie(0)->sync_with_stdio(0);
    cin.exceptions(cin.failbit);

    int k, m, o;
    cin >> k >> n >> m >> o;
    rep(i, 0, m) {
        int u, v, w;
        cin >> u >> v >> w;
        graph[u].emplace_back(v, w);
    }

    if (k == 1) {
        solve(0, 0);
        while (o--) {
            int a, b;
            cin >> a >> b;
            if (b < a || rgt[a] < b)
                cout << -1 << endl;
            else
                cout << dist[b] - dist[a] << endl;
        }

    } else {
        int preva = -1;
        set<ii> pq;
        rep(i, 0, o) {
            int a, b;
            cin >> a >> b;

            if (preva != a) {
                fill(dist, dist + n, INF);
                dist[a] = 0;
                rep(i, 0, n) pq.insert({dist[i], i});

                while (!pq.empty()) {
                    int d, u;
                    tie(d, u) = *pq.begin();
                    pq.erase(pq.begin());

                    trav(edge, graph[u]) {
                        int v, w;
                        tie(v, w) = edge;
                        if (d + w >= dist[v]) continue;

                        pq.erase({dist[v], v});
                        dist[v] = d + w;
                        pq.emplace(d + w, v);
                    }
                }
            }
            preva = a;
            if (dist[b] == INF)
                cout << "-1\n";
            else
                cout << dist[b] << endl;
        }
    }
    return 0;
}

• Subtask 1: 7 / 7
• Subtask 2: 10 / 10
• Subtask 3: 8 / 8
• Subtask 4: 0 / 31
• Subtask 5: 0 / 44