Submission #709908

#	Time	Username	Problem	Language	Result	Execution time	Memory
709908		noedit	Jakarta Skyscrapers (APIO15_skyscraper)	C++17	57 / 100	1086 ms	247308 KiB

skyscraper

#include <bits/stdc++.h>
//#pragma GCC optimize("Ofast")
//#pragma GCC optimize("unroll-loops")

using namespace std;

typedef long long ll;

const int INF = 1e9;
const int B = 280;
const int MAXN = 3e4 + 5;

vector<pair<int, int> > d;

int dist[MAXN][B];
vector<array<short, 3> > g[MAXN][B];

signed main()
{
    //ifstream cin("input.txt");
    //ofstream cout("output.txt");
    ios_base::sync_with_stdio(false);
    cin.tie(0);
    cout.tie(0);
    int n, m;
    cin >> n >> m;
    d.resize(m);
    vector<int> big;
    for (int i = 0; i < m; i++)
    {
        cin >> d[i].first >> d[i].second;
        if (d[i].second >= B)
        {
            big.push_back(i);
        }
    }
    for (int i = 0; i < n; i++)
        for (int j = 0; j < B; j++)
            dist[i][j] = INF;
    for (int i = 0; i < m; i++)
    {
        if (d[i].second >= B) continue;
        g[d[i].first][0].push_back({d[i].first, d[i].second, 0});
    }
//    for (int i = 0; i < n; i++)
//    {
//        for (int j = 1; j < B; j++)
//        {
//            if (i - j >= 0)
//            {
//                g[i][j].push_back({i - j, 0, 1});
//                g[i][j].push_back({i - j, j, 1});
//            }
//            if (i + j < n)
//            {
//                g[i][j].push_back({i + j, 0, 1});
//                g[i][j].push_back({i + j, j, 1});
//            }
//        }
//    }
    for (auto& i : big)
    {
        for (int j = d[i].first, k = 0; j < n; j += d[i].second, k++)
        {
            g[d[i].first][0].push_back({j, 0, k});
        }
        for (int j = d[i].first, k = 0; j >= 0; j -= d[i].second,  k++)
        {
            g[d[i].first][0].push_back({j, 0, k});
        }
    }
    set<array<int, 3> > st;
    st.insert({0, d[0].first, 0});
    dist[d[0].first][0] = 0;
    while (!st.empty())
    {
        auto [dst, pos, pw] = *st.begin();
        st.erase(st.begin());
        if (dst > dist[pos][pw]) continue;
        if (pw > 0)
        {
            vector<array<short, 3> > to;
            if (pos - pw >= 0)
            {
                if (dist[pos - pw][pw] > dst + 1)
                {
                    st.erase({dist[pos - pw][pw], pos - pw, pw});
                    dist[pos - pw][pw] = dst + 1;
                    st.insert({dist[pos - pw][pw], pos - pw, pw});
                }
                if (dist[pos - pw][0] > dst + 1)
                {
                    st.erase({dist[pos - pw][0], pos - pw, 0});
                    dist[pos - pw][0] = dst + 1;
                    st.insert({dist[pos - pw][0], pos - pw, 0});
                }
            }
            if (pos + pw < n)
            {
                if (dist[pos + pw][pw] > dst + 1)
                {
                    st.erase({dist[pos + pw][pw], pos + pw, pw});
                    dist[pos + pw][pw] = dst + 1;
                    st.insert({dist[pos + pw][pw], pos + pw, pw});
                }
                if (dist[pos + pw][0] > dst + 1)
                {
                    st.erase({dist[pos + pw][0], pos + pw, 0});
                    dist[pos + pw][0] = dst + 1;
                    st.insert({dist[pos + pw][0], pos + pw, 0});
                }
            }
        }
        for (auto& [psu, pwu, w] : g[pos][pw])
        {
            if (dist[psu][pwu] > dst + w)
            {
                st.erase({dist[psu][pwu], psu, pwu});
                dist[psu][pwu] = dst + w;
                st.insert({dist[psu][pwu], psu, pwu});
            }
        }
    }
    int mn = INF;
    for (int i = 0; i < B; i++)
        mn = min(mn, dist[d[1].first][i]);
    if (mn == INF)
        cout << -1;
    else
        cout << mn;
    return 0;
}
/*
small
(i, j) -1> (i - j, 0), (i + j, 0)
(i, 0) -0> (i, j)
(i, j) -1> (i - j, j), (i + j, j)
large
(i, 0) -1> (i + j, 0)
(i, 0) -1> (i - j, 0)
*/

Compilation message (stderr)

skyscraper.cpp: In function 'int main()':
skyscraper.cpp:43:42: warning: narrowing conversion of 'd.std::vector<std::pair<int, int> >::operator[](((std::vector<std::pair<int, int> >::size_type)i)).std::pair<int, int>::first' from 'int' to 'short int' [-Wnarrowing]
   43 |         g[d[i].first][0].push_back({d[i].first, d[i].second, 0});
skyscraper.cpp:43:54: warning: narrowing conversion of 'd.std::vector<std::pair<int, int> >::operator[](((std::vector<std::pair<int, int> >::size_type)i)).std::pair<int, int>::second' from 'int' to 'short int' [-Wnarrowing]
   43 |         g[d[i].first][0].push_back({d[i].first, d[i].second, 0});
skyscraper.cpp:65:41: warning: narrowing conversion of 'j' from 'int' to 'short int' [-Wnarrowing]
   65 |             g[d[i].first][0].push_back({j, 0, k});
      |                                         ^
skyscraper.cpp:65:47: warning: narrowing conversion of 'k' from 'int' to 'short int' [-Wnarrowing]
   65 |             g[d[i].first][0].push_back({j, 0, k});
      |                                               ^
skyscraper.cpp:69:41: warning: narrowing conversion of 'j' from 'int' to 'short int' [-Wnarrowing]
   69 |             g[d[i].first][0].push_back({j, 0, k});
      |                                         ^
skyscraper.cpp:69:47: warning: narrowing conversion of 'k' from 'int' to 'short int' [-Wnarrowing]
   69 |             g[d[i].first][0].push_back({j, 0, k});
      |                                               ^

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