Submission #847385

#	Time	Username	Problem	Language	Result	Execution time	Memory
847385		manhlinh1501	Jakarta Skyscrapers (APIO15_skyscraper)	C++17	100 / 100	449 ms	29392 KiB

skyscraper

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

using pii = pair<int, int>;

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

#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][200];
vector<int> adj[N];
priority_queue<node, vector<node>, greater<node>> Q;
int ans = oo;
int start, finish;
bool vis[N];

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

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

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

        if(i == 0)
            start = u;

        if(i == 1)
            finish = u;
    }

    memset(dist, 0x3f, sizeof dist);

    dist[start][0] = 0;
    Q.emplace(0, start, 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 == finish)
            return cout << dist[finish][cur], 0;

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

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

        if(vis[u])
            continue;

        vis[u] = true;

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

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

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

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

    cout << -1;
}

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