제출 #635895

#제출 시각아이디문제언어결과실행 시간메모리
635895tabrRectangles (IOI19_rect)C++17
72 / 100
5106 ms1037324 KiB
#include <bits/stdc++.h> using namespace std; #ifdef tabr #include "library/debug.cpp" #else #define debug(...) #endif struct dsu { vector<int> p; vector<int> sz; vector<int> mn; vector<int> mx; int n; dsu(int _n) : n(_n) { p = vector<int>(n); iota(p.begin(), p.end(), 0); sz = vector<int>(n, 1); mx = p; mn = p; } inline int get(int x) { if (p[x] == x) { return x; } else { return p[x] = get(p[x]); } } inline bool unite(int x, int y) { x = get(x); y = get(y); if (x == y) { return false; } p[x] = y; sz[y] += sz[x]; mn[y] = min(mn[y], mn[x]); mx[y] = max(mx[y], mx[x]); return true; } inline bool same(int x, int y) { return (get(x) == get(y)); } inline int size(int x) { return sz[get(x)]; } inline bool root(int x) { return (x == get(x)); } }; #include <ext/pb_ds/assoc_container.hpp> using namespace __gnu_pbds; template <typename T> using pbds = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>; pbds<int> segs[2500][2500]; set<pair<int, int>> ngs[2500][2500]; int first_ng[2500][2500]; int last_ng[2500][2500]; long long count_rectangles(vector<vector<int>> a) { int h = (int) a.size(); int w = (int) a[0].size(); for (int j = 0; j < w; j++) { vector<int> s; for (int i = h - 1; i >= 0; i--) { while (!s.empty() && a[s.back()][j] < a[i][j]) { s.pop_back(); } if (!s.empty()) { first_ng[i][j] = s.back(); } else { first_ng[i][j] = h; } s.emplace_back(i); } } for (int j = 0; j < w; j++) { vector<int> s; for (int i = 0; i < h; i++) { while (!s.empty() && a[s.back()][j] < a[i][j]) { s.pop_back(); } if (!s.empty()) { last_ng[i][j] = s.back(); } else { last_ng[i][j] = -1; } s.emplace_back(i); } } long long res = 0; set<pair<int, int>> cnt; for (int i = 1; i < h - 1; i++) { vector<vector<int>> bound(w); vector<int> order(w); iota(order.begin(), order.end(), 0); sort(order.begin(), order.end(), [&](int x, int y) { return a[i][x] < a[i][y]; }); dsu uf(w); for (int x = 0, y = 0; x < w; x = y) { while (y < w && a[i][order[x]] == a[i][order[y]]) { y++; } for (int l = x; l < y; l++) { int j = order[l]; if (j - 1 >= 0 && a[i][j] >= a[i][j - 1]) { uf.unite(j - 1, j); } if (j + 1 < w && a[i][j] >= a[i][j + 1]) { uf.unite(j + 1, j); } } for (int l = x; l < y; l++) { int j = order[l]; if (uf.root(j) && uf.mn[j] > 0 && uf.mx[j] < w - 1) { bound[uf.mx[j]].emplace_back(uf.mn[j]); } } } set<pair<int, int>> new_cnt; vector<int> v_min, v_max; int up_last = 0; int down_last = 0; for (int j = 1; j < w - 1; j++) { while (!v_min.empty() && first_ng[i - 1][v_min.back()] >= first_ng[i - 1][j]) { v_min.pop_back(); } v_min.emplace_back(j); while (!v_max.empty() && last_ng[i + 1][v_max.back()] <= last_ng[i + 1][j]) { v_max.pop_back(); } v_max.emplace_back(j); if (a[i][j] >= a[i - 1][j]) { up_last = j; } if (a[i][j] >= a[i + 1][j]) { down_last = j; } for (int k : bound[j]) { new_cnt.emplace(k, j); if (up_last < k) { segs[k][j].insert(i); ngs[k][j].emplace(first_ng[i - 1][*lower_bound(v_min.begin(), v_min.end(), k)], i); } auto iter = ngs[k][j].begin(); while (iter != ngs[k][j].end() && iter->first == i) { segs[k][j].erase(iter->second); iter = ngs[k][j].erase(iter); } if (down_last < k) { res += (int) (segs[k][j].size() - segs[k][j].order_of_key(last_ng[i + 1][*lower_bound(v_max.begin(), v_max.end(), k)] + 1)); } } } for (auto p : cnt) { if (!new_cnt.count(p)) { segs[p.first][p.second].clear(); ngs[p.first][p.second].clear(); } } swap(cnt, new_cnt); } return res; } #ifdef tabr mt19937 rng((unsigned int) chrono::steady_clock::now().time_since_epoch().count()); int rand_int(int a, int b) { // [a, b] return uniform_int_distribution<int>(a, b)(rng); } int main() { ios::sync_with_stdio(false); cin.tie(0); debug(count_rectangles({{4, 8, 7, 5, 6}, {7, 4, 10, 3, 5}, {9, 7, 20, 14, 2}, {9, 14, 7, 3, 6}, {5, 7, 5, 2, 7}, {4, 5, 13, 5, 6}})); debug(count_rectangles({{5, 7, 5}, {9, 4, 7}, {9, 7, 20}, {7, 4, 10}, {4, 8, 7}})); debug(count_rectangles({{10, 10, 10}, {10, 9, 10}, {10, 0, 10}, {10, 1, 10}, {10, 5, 10}, {10, 10, 10}})); vector<vector<int>> a(6, vector<int>(3, 10)); for (int i = 1; i < 5; i++) { for (int j = 1; j < 2; j++) { a[i][j] = rand_int(0, 9); } } for (auto b : a) debug(b); debug(count_rectangles(a)); return 0; } #endif
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