Submission #1095962

#	Time	Username	Problem	Language	Result	Execution time	Memory
1095962		yoav_s	Building Skyscrapers (CEOI19_skyscrapers)	C++17	22 / 100	3548 ms	22780 KiB

skyscrapers

#include <bits/stdc++.h>

using namespace std;

typedef long long ll;
typedef vector<ll> v;
typedef vector<v> vv;
typedef vector<vv> vvv;
typedef pair<ll, ll> p;
typedef vector<p> vp;
typedef vector<vp> vvp;
typedef vector<vvp> vvvp;
typedef pair<ll, p> tri;
typedef vector<tri> vtri;
typedef vector<vtri> vvtri;
typedef vector<vvtri> vvvtri;
typedef vector<bool> vb;
typedef vector<vb> vvb;
typedef vector<vvb> vvvb;

#define f first
#define s second
#define pb push_back
#define eb emplace_back
#define all(v) (v).begin(),(v).end()

const ll INF = 1e18;
const ll mod = 1e9 + 7;

int main()
{
    ios_base::sync_with_stdio(false); cin.tie(NULL); cout.tie(NULL);
    ll n, t;
    cin >> n >> t;
    vp cells(n);
    for (ll i=  0; i < n; i++) cin >> cells[i].f >> cells[i].s;
    v relevantX, relevantY;
    for (ll i = 0; i < n; i++)
    {
        relevantX.pb(cells[i].f - 1);
        relevantX.pb(cells[i].f);
        relevantX.pb(cells[i].f + 1);
        relevantY.pb(cells[i].s - 1);
        relevantY.pb(cells[i].s);
        relevantY.pb(cells[i].s + 1);
    }
    sort(all(relevantX)); sort(all(relevantY));
    relevantX.erase(unique(all(relevantX)), relevantX.end()); relevantY.erase(unique(all(relevantY)), relevantY.end());
    map<ll, ll> xShrink;
    map<ll, ll> yShrink;
    for (ll i = 0; i < relevantX.size(); i++) xShrink[relevantX[i]] = i + 1;
    for (ll i = 0; i < relevantY.size(); i++) yShrink[relevantY[i]] = i + 1;
    for (ll i = 0; i < n; i++) cells[i] = p(xShrink[cells[i].f], yShrink[cells[i].s]);
    ll maxX = relevantX.size() + 2, maxY = relevantY.size() + 2;
    vvb occupied(maxX, vb(maxY, false));
    for (ll i = 0; i < n; i++) occupied[cells[i].f][cells[i].s] = true;
    set<ll, greater<ll>> available;
    for (ll i = 0; i < n; i++) available.insert(i);
    v order;
    vb possible(n, false);
    vv adjacentStructures(n);
    for (ll i = 0; i < n; i++)
    {
        for (ll j = i + 1; j < n; j++)
        {
            if (abs(cells[i].f - cells[j].f) <= 1 && abs(cells[i].s - cells[j].s) <= 1)
            {
                adjacentStructures[i].pb(j);
                adjacentStructures[j].pb(i);
            }
        }
    }
    vb visited(n, false);
    stack<ll> dfs; dfs.push(0);
    ll cnt = 0;
    while (!dfs.empty())
    {
        auto top = dfs.top();
        dfs.pop();
        if (visited[top]) continue;
        visited[top] = true; cnt++;
        for (ll x : adjacentStructures[top]) dfs.push(x);
    }
    if (cnt != n)
    {
        cout << "NO\n";
        return 0;
    }
    for (ll i = n - 1; i >= 0; i--)
    {
        bool done = false;
        for (ll x : available)
        {
            vv supplyComp(maxX, v(maxY));
            vvvp newSupplyGraph(maxX, vvp(maxY));
            occupied[cells[x].f][cells[x].s] = false;
            for (ll i = 0; i < maxX; i++)
            {
                for (ll j = 0; j < maxY; j++)
                {
                    if (occupied[i][j]) continue;
                    if (i + 1 < maxX && !occupied[i + 1][j])
                    {
                        newSupplyGraph[i][j].eb(i+1,j);
                        newSupplyGraph[i+1][j].eb(i,j);
                    }
                    if (j + 1 < maxY && !occupied[i][j + 1])
                    {
                        newSupplyGraph[i][j].eb(i,j+1);
                        newSupplyGraph[i][j+1].eb(i,j);
                    }
                }
            }
            vv component(maxX, v(maxY, -1));
            ll comp = 0;
            for (ll i = 0; i < maxX; i++)
            {
                for (ll j = 0; j < maxY; j++)
                {
                    if (component[i][j] != -1) continue;
                    stack<p> dfs;
                    dfs.emplace(i, j);
                    while (!dfs.empty())
                    {
                        auto top = dfs.top();
                        dfs.pop();
                        if (component[top.f][top.s] != -1) continue;
                        component[top.f][top.s] = comp;
                        for (auto x : newSupplyGraph[top.f][top.s]) dfs.push(x);
                    }
                    comp++;
                }
            }
            bool poss = true;
            if (component[cells[x].f][cells[x].s] != component[maxX - 1][maxY - 1]) poss = false;
            else if (i > 1)
            {
                vb visited(n, false);
                auto ptr = available.begin();
                if (*ptr == x) ptr++;
                ll start = *ptr;
                stack<ll> dfs; dfs.push(start);
                ll cnt = 0;
                while (!dfs.empty())
                {
                    auto top = dfs.top();
                    dfs.pop();
                    if (available.count(top) == 0 || top == x || visited[top]) continue;
                    visited[top] = true; cnt++;
                    for (ll x : adjacentStructures[top]) dfs.push(x);
                }
                if (cnt != available.size() - 1)
                {
                    poss = false;
                }
            }
            if (!poss)
            {
                occupied[cells[x].f][cells[x].s] = true;
                continue;
            }
            available.erase(x);
            order.pb(x);
            done = true;
            break;
        }
        if (!done)
        {
            cout << "NO\n";
            return 0;
        }
    }
    reverse(all(order));
    cout << "YES\n";
    for (ll x : order) cout << x + 1 << "\n";
    return 0;
}

Compilation message (stderr)

skyscrapers.cpp: In function 'int main()':
skyscrapers.cpp:51:22: warning: comparison of integer expressions of different signedness: 'll' {aka 'long long int'} and 'std::vector<long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   51 |     for (ll i = 0; i < relevantX.size(); i++) xShrink[relevantX[i]] = i + 1;
      |                    ~~^~~~~~~~~~~~~~~~~~
skyscrapers.cpp:52:22: warning: comparison of integer expressions of different signedness: 'll' {aka 'long long int'} and 'std::vector<long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   52 |     for (ll i = 0; i < relevantY.size(); i++) yShrink[relevantY[i]] = i + 1;
      |                    ~~^~~~~~~~~~~~~~~~~~
skyscrapers.cpp:152:25: warning: comparison of integer expressions of different signedness: 'll' {aka 'long long int'} and 'std::set<long long int, std::greater<long long int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  152 |                 if (cnt != available.size() - 1)
      |                     ~~~~^~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 8 / 8
• Subtask 2: 14 / 14
• Subtask 3: 0 / 12
• Subtask 4: 0 / 17
• Subtask 5: 0 / 20
• Subtask 6: 0 / 10
• Subtask 7: 0 / 19