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void solve(istream& in, ostream& out) { | |
int n = next<int>(in); | |
Graph g; | |
Graph::Node s = g.addNode(), t = g.addNode(); | |
auto cap = g.arcMap<int>(); | |
vector<vector<Graph::Node>> levelsIn, levelsOut; | |
levelsIn.push_back(g.addNodes(n)); | |
levelsOut.push_back(g.addNodes(n)); | |
forn (int, i, n) { | |
g.addEdge(s, levelsIn[0][i]).withUV(cap, 1); | |
g.addEdge(levelsOut[0][i], t).withUV(cap, 1); | |
} | |
for (int l = 1; (1 << l) <= n; ++l) { | |
levelsIn.push_back(g.addNodes(n - (1 << l) + 1)); | |
levelsOut.push_back(g.addNodes(n - (1 << l) + 1)); | |
forn (int, i, n - (1 << l) + 1) { | |
g.addEdge(levelsIn[l - 1][i], levelsIn[l][i]).withUV(cap, n); | |
g.addEdge(levelsIn[l - 1][i + (1 << (l - 1))], levelsIn[l][i]).withUV(cap, n); | |
g.addEdge(levelsOut[l][i], levelsOut[l - 1][i]).withUV(cap, n); | |
g.addEdge(levelsOut[l][i], levelsOut[l - 1][i + (1 << (l - 1))]).withUV(cap, n); | |
} | |
} | |
int qs = next<int>(in); | |
using evt = tuple<int, int, pair<int, int>>; | |
vector<evt> evs; | |
forn (int, q, qs) { | |
int x1 = next<int>(in) - 1; | |
int y1 = next<int>(in) - 1; | |
int x2 = next<int>(in) - 1; | |
int y2 = next<int>(in) - 1; | |
evs.push_back(evt{x1, +1, {y1, y2 + 1}}); | |
evs.push_back(evt{x2 + 1, -1, {y1, y2 + 1}}); | |
} | |
evs.push_back(evt{0, -1, {0, n}}); | |
evs.push_back(evt{n, +1, {0, n}}); | |
sort(all(evs)); | |
auto insertRect = [&](int x0, int x1, int y0, int y1) { | |
if (x0 == x1 || y0 == y1) { | |
return; | |
} | |
int dx = 0, dy = 0; | |
while (x0 + (1 << (dx + 1)) <= x1) { | |
++dx; | |
} | |
while (y0 + (1 << (dy + 1)) <= y1) { | |
++dy; | |
} | |
auto u = g.addNode(); | |
g.addEdge(levelsIn[dx][x0], u).withUV(cap, n); | |
g.addEdge(levelsIn[dx][x1 - (1 << dx)], u).withUV(cap, n); | |
g.addEdge(u, levelsOut[dy][y0]).withUV(cap, n); | |
g.addEdge(u, levelsOut[dy][y1 - (1 << dy)]).withUV(cap, n); | |
dbg(x0 + 1, y0 + 1, x1, y1, u.id); | |
}; | |
map<int, pair<int, int>> ranges; | |
for (auto& e : evs) { | |
int x = get<0>(e); | |
auto& range = get<2>(e); | |
if (get<1>(e) == -1) { | |
ranges[range.first] = {range.second, x}; | |
} else { | |
auto it = ranges.upper_bound(range.first); | |
--it; | |
pair<int, int> outer; | |
outer.first = it->first; | |
while (it != ranges.end() && it->first < range.second) { | |
insertRect(it->second.second, x, it->first, it->second.first); | |
outer.second = it->second.first; | |
auto jt = it; | |
it++; | |
ranges.erase(jt); | |
} | |
if (outer.first < range.first) { | |
ranges[outer.first] = {range.first, x}; | |
} | |
if (range.second < outer.second) { | |
ranges[range.second] = {outer.second, x}; | |
} | |
} | |
} | |
PushRelabel<int> f(g, cap); | |
out << f.run(s, t) << "\n"; | |
} |
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