Submission #1162178

#	Time	Username	Problem	Language	Result	Execution time	Memory
1162178		minhpk	Jakarta Skyscrapers (APIO15_skyscraper)	C++20	57 / 100	1098 ms	52728 KiB

skyscraper

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

int a, b;
vector<int> z[1000005];
int blocksize;
pair<int, int> mark[30005];


struct node {
    int val, pos, type;
    bool operator>(const node &other) const {
        return val > other.val;
    }
};


int base;
inline long long encode(int pos, int type) {
    return (long long) pos * base + type;
}


map<long long, int> dist;

void dijkstra() {
    priority_queue<node, vector<node>, greater<node>> q;
    long long key0 = encode(mark[0].first, mark[0].second);
    dist[key0] = 0;
    q.push({0, mark[0].first, mark[0].second});

    while (!q.empty()) {
        node cur = q.top();
        q.pop();
        int d = cur.val, pos = cur.pos, type = cur.type;
        long long curKey = encode(pos, type);
        if (dist[curKey] < d) continue;

        if (type == 0) {
            for (int p : z[pos]) {

                int newPos = pos + p;
                if (newPos < a) {
                    long long key = encode(newPos, p);
                    int nd = d + 1;
                    if (!dist.count(key) || dist[key] > nd) {
                        dist[key] = nd;
                        q.push({nd, newPos, p});
                    }
                }

                newPos = pos - p;
                if (newPos >= 0) {
                    long long key = encode(newPos, p);
                    int nd = d + 1;
                    if (!dist.count(key) || dist[key] > nd) {
                        dist[key] = nd;
                        q.push({nd, newPos, p});
                    }
                }
            }
        } else {

            long long key0 = encode(pos, 0);
            if (!dist.count(key0) || dist[key0] > d) {
                dist[key0] = d;
                q.push({d, pos, 0});
            }

            if (type > blocksize) {
                int step = 1;
                while (pos + step * type < a) {
                    int newPos = pos + step * type;
                    long long key = encode(newPos, 0);
                    int nd = d + step;
                    if (!dist.count(key) || dist[key] > nd) {
                        dist[key] = nd;
                        q.push({nd, newPos, 0});
                    }
                    step++;
                }
                step = 1;
                while (pos - step * type >= 0) {
                    int newPos = pos - step * type;
                    long long key = encode(newPos, 0);
                    int nd = d + step;
                    if (!dist.count(key) || dist[key] > nd) {
                        dist[key] = nd;
                        q.push({nd, newPos, 0});
                    }
                    step++;
                }
            } else {
                int newPos = pos + type;
                if (newPos < a) {
                    long long key = encode(newPos, type);
                    int nd = d + 1;
                    if (!dist.count(key) || dist[key] > nd) {
                        dist[key] = nd;
                        q.push({nd, newPos, type});
                    }
                }
                newPos = pos - type;
                if (newPos >= 0) {
                    long long key = encode(newPos, type);
                    int nd = d + 1;
                    if (!dist.count(key) || dist[key] > nd) {
                        dist[key] = nd;
                        q.push({nd, newPos, type});
                    }
                }
            }
        }
    }
}

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

    cin >> a >> b;
    blocksize = sqrt(a);
    base = a + 1;

    for (int i = 0; i < b; i++){
        int x, y;
        cin >> x >> y;
        z[x].push_back(y);
        mark[i] = {x, y};
    }
    if(b == 0){
        cout << -1;
        return 0;
    }


  //  dist.reserve(100000);

    dijkstra();

    long long finalKey = encode(mark[1].first, 0);
    if(dist.count(finalKey)){
        cout << dist[finalKey];
    } else {
        cout << -1;
    }
    return 0;
}

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