Submission #847142

#	Time	Username	Problem	Language	Result	Execution time	Memory
847142		vjudge1	Jakarta Skyscrapers (APIO15_skyscraper)	C++17	22 / 100	6 ms	25176 KiB

skyscraper

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

using pii = pair<int, int>;

const int N = 3e4 + 5;
const int oo = 1e9;
const int SQRT = 200;

#define eb emplace_back

struct node {
    int w, u, s;

    node() {
        w = u = s = 0;
    }

    node(int w, int u, int s) : w(w), u(u), s(s) {}

    friend bool operator > (node a, node b) {
        return a.w > b.w;
    }
};

int n, m;
int dist[N][SQRT];
pii a[N];
vector<int> adj[N];
priority_queue<node, vector<node>, greater<node>> Q;
bool vis[N];
int ans = oo;

void update(int u, int v, int w, int cur) {
    if(dist[v][cur] > dist[u][cur] + w) {
        dist[v][cur] = dist[u][cur] + w;
        Q.emplace(dist[v][cur], v, cur);
    }
}

int main() {
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);
    cin >> n >> m;

    for(int i = 0; i < m; i++) {
        int u, v;
        cin >> u >> v;
        adj[u].eb(v);
        a[i] = {u, v};
    }

    memset(dist, 0x3f, sizeof dist);

    dist[a[0].first][0] = 0;
    Q.emplace(0, a[0].first, 0);

    while(!Q.empty()) {
        node top = Q.top();
        Q.pop();

        int u = top.u;
        int cur = top.s;

        if(dist[u][cur] != top.w)
            continue;

        if(u == a[1].first)
            ans = min(ans, dist[a[1].first][cur]);

        if(cur) {
            if(u + cur <= n)
                update(u, u + cur, 1, cur);

            if(u - cur >= 0)
                update(u, u - cur, 1, cur);
        }

        for(int v : adj[u]) {
            if(dist[u][v] > dist[u][cur])
                dist[u][v] = dist[u][cur];

            if(v >= SQRT) {
                for(int j = 1; u + j * v <= n; j++)
                    update(u, u + j * v, j, 0);

                for(int j = 1; u - j * v >= 0; j++)
                    update(u, u - j * v, j, 0);

            } else {
                if(u + v <= n)
                    update(u, u + v, 1, v);

                if(u - v >= 0)
                    update(u, u - v, 1, v);
            }
        }
    }

    cout << (ans == oo ? -1 : ans);
}
/*
5 3
0 2
1 1
4 1
*/

• Subtask 1: 10 / 10
• Subtask 2: 12 / 12
• Subtask 3: 0 / 14
• Subtask 4: 0 / 21
• Subtask 5: 0 / 43