Submission #565393

#TimeUsernameProblemLanguageResultExecution timeMemory
565393shrimbBuilding Skyscrapers (CEOI19_skyscrapers)C++17
17 / 100
985 ms40588 KiB
#pragma GCC optimize ("Ofast") #pragma GCC target ("avx,avx2,fma") #include"bits/stdc++.h" using namespace std; #include <ext/pb_ds/assoc_container.hpp> #include <ext/pb_ds/tree_policy.hpp> using namespace __gnu_pbds; template<class x> using ordered_set = tree<x, null_type,less<x>, rb_tree_tag,tree_order_statistics_node_update>; #define int long long #define endl '\n' #define mod 1000000007 //\ #define mod 1686876991 const int maxn = 150001; const int dx[] = {-1, 1, 0, 0, 1, 1, -1, -1}; const int dy[] = {0, 0, 1, -1, -1, 1, -1, 1}; // const int roundx[] = {1, 1, 0, -1, -1, -1, 0, 1, 1}; const int roundy[] = {0, 1, 1, 1, 0, -1, -1, -1, 0}; struct cell {int x, y, id;}; int n, t, ID = 0, buf; int x[maxn], y[maxn]; cell cells[maxn]; int dsu[4 * maxn]; vector<pair<int,int>> vec[4 * maxn]; bool out[4 * maxn]; pair<int,int> mp[4 * maxn]; unordered_map<int,unordered_map<int,int>> Empty, Full; // maps cell to dsu set<cell> active, expendable; bool operator < (const cell& a, const cell& b) { return a.id > b.id; } int Find (int x) { return dsu[x] == x ? x : dsu[x] = Find(dsu[x]); } void check (const cell &c) { auto [u, v, id] = c; int prev = -1; bool artic = 0, sep = 0; vector<int> to_reset; for (int w = 0 ; w < 9 ; w++) { int d = w%8; int u2 = u + roundx[d]; int v2 = v + roundy[d]; if (Full[u2].count(v2)) sep = 1; else { if (d & 1) { continue; } int cmp = Find(Empty[u2][v2]); if (mp[cmp].first != -1 and sep == 1) { auto [pu, pv] = mp[cmp]; bool bad = 0; for (int ww = w ; ; ww++) { int d2 = ww % 8; int u3 = u + roundx[d2]; int v3 = v + roundy[d2]; if (u3 == pu and v3 == pv) { break; } else { if (Full[u3].count(v3)) { bad = 1; break; } } } if (bad) artic = 1; } mp[cmp] = {u2, v2}; to_reset.push_back(cmp); sep = 0; prev = cmp; } } for (int cmp : to_reset) { mp[cmp] = {-1,-1}; } bool isout = 0; if (!artic) { for (int d = 0 ; d < 4 ; d++) { int u2 = u + dx[d]; int v2 = v + dy[d]; if (Empty[u2].count(v2)) { int cmp = Find(Empty[u2][v2]); if (out[cmp]) isout = 1; } } } if (isout and !artic) expendable.insert(c); else expendable.erase(c); } void Union (int a, int b) { int x = Find(a), y = Find(b); if (x == y) return; if (vec[x].size() < vec[y].size()) { out[y] |= out[x]; dsu[x] = y; for (auto [u, v] : vec[x]) { vec[y].push_back({u, v}); for (int d = 0 ; d < 8 ; d++) { if (Full[u + dx[d]].count(v + dy[d])) check(cells[Full[u + dx[d]][v + dy[d]]]); } } vec[x].clear(); } else { out[x] |= out[y]; dsu[y] = x; for (auto [u, v] : vec[y]) { vec[x].push_back({u, v}); for (int d = 0 ; d < 8 ; d++) { if (Full[u + dx[d]].count(v + dy[d])) check(cells[Full[u + dx[d]][v + dy[d]]]); } } vec[y].clear(); } } signed main () { cin.tie(0)->sync_with_stdio(0); cin >> n >> t; for (auto& [i, j] : mp) i = j = -1; for (int i = 0 ; i < n ; i++) { cin >> x[i] >> y[i]; cells[i] = {x[i], y[i], i}; Full[x[i]][y[i]] = i; active.insert(cells[i]); } if (n > 1) { for (int i = 0 ; i < n ; i++) { bool good = 0; for (int d = 0 ; d < 8 ; d++) { int u = x[i] + dx[d]; int v = y[i] + dy[d]; good |= Full[u].count(v); } if (!good) { cout << "NO\n"; return 0; } } } /* set at leat one node as out (for reference) */ { pair<int,int> mn = {x[0], y[0]}; for (int i = 0 ; i < n ; i++) { mn = min(mn, {x[i], y[i]}); } auto [u, v] = mn; u--; int id = Empty[u][v] = ID++; dsu[id] = id; vec[id].push_back({u, v}); out[id] = 1; } for (int i = 0 ; i < n ; i++) { for (int d = 0 ; d < 8 ; d++) { int u = x[i] + dx[d]; int v = y[i] + dy[d]; if (!Full[u].count(v) and !Empty[u].count(v)) { int id = Empty[u][v] = ID++; dsu[id] = id; vec[id].push_back({u, v}); } } } for (int i = 0 ; i < n ; i++) { for (int d = 0 ; d < 8 ; d++) { int u = x[i] + dx[d]; int v = y[i] + dy[d]; if (!Full[u].count(v)) { for (int d2 = 0 ; d2 < 4 ; d2++) { int u2 = u + dx[d2]; int v2 = v + dy[d2]; if (Empty[u2].count(v2)) { Union(Empty[u][v], Empty[u2][v2]); } } } } } for (int i = 0 ; i < n ; i++) check(cells[i]); cout << "YES\n"; vector<int> ans; while (expendable.size()) { auto [a, b, c] = *expendable.begin(); expendable.erase(expendable.begin()); ans.push_back(c + 1); Full[a].erase(b); int id = Empty[a][b] = ID++; dsu[id] = id; vec[id].push_back({a, b}); for (int d = 0 ; d < 4 ; d++) { int u = a + dx[d]; int v = b + dy[d]; if (!Full[u].count(v) and !Empty[u].count(v)) { assert(0); int id = Empty[u][v] = ID++; dsu[id] = id; vec[id].push_back({u, v}); } if (Empty[u].count(v)) { Union(Empty[u][v], id); } } for (int d = 0 ; d < 8 ; d++) { int u = a + dx[d]; int v = b + dy[d]; if (Full[u].count(v)) check(cells[Full[u][v]]); } } reverse(ans.begin(), ans.end()); for (int i : ans) cout << i << "\n"; }

Compilation message (stderr)

skyscrapers.cpp:17:1: warning: multi-line comment [-Wcomment]
   17 | //\
      | ^
skyscrapers.cpp: In function 'void check(const cell&)':
skyscrapers.cpp:49:9: warning: variable 'prev' set but not used [-Wunused-but-set-variable]
   49 |     int prev = -1;
      |         ^~~~
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