Submission #420898

#TimeUsernameProblemLanguageResultExecution timeMemory
420898yuto1115Rectangles (IOI19_rect)C++17
59 / 100
5061 ms704944 KiB
#include "rect.h" #include <bits/stdc++.h> #define rep(i, n) for(ll i = 0; i < ll(n); i++) #define rep2(i, s, n) for(ll i = ll(s); i < ll(n); i++) #define rrep(i, n) for(ll i = ll(n)-1; i >= 0; i--) #define all(a) a.begin(),a.end() #define rall(a) a.rbegin(),a.rend() #define pb push_back #define eb emplace_back using namespace std; using ll = long long; using P = pair<int, int>; using vi = vector<int>; using vvi = vector<vi>; using vvvi = vector<vvi>; using vl = vector<ll>; using vvl = vector<vl>; using vp = vector<P>; using vvp = vector<vp>; using vb = vector<bool>; using vvb = vector<vb>; using vs = vector<string>; template<class T> bool chmin(T &a, T b) { if (a > b) { a = b; return true; } return false; } template<class T> bool chmax(T &a, T b) { if (a < b) { a = b; return true; } return false; } const int inf = 1001001001; const ll linf = 1001001001001001001; class BIT { int n; vl v; public: BIT(int n) : n(n), v(n + 1, 0) {} void add(int i, int x) { assert(0 <= i and i < n); i++; while (i <= n) { v[i] += x; i += i & -i; } } ll sum(int i) { assert(0 <= i and i < n); i++; ll res = 0; while (i >= 1) { res += v[i]; i -= i & -i; } return res; } }; ll count_rectangles(vvi a) { int n = a.size(), m = a[0].size(); if (n < 3 or m < 3) return 0; vvvi col_fix(m, vvi(m)); rep2(i, 1, n - 1) { stack<int> st; rep(j, m) { while (!st.empty() and a[i][st.top()] < a[i][j]) { if (st.top() < j - 1) col_fix[st.top() + 1][j - 1].pb(i); st.pop(); } if (!st.empty()) { if (st.top() < j - 1) col_fix[st.top() + 1][j - 1].pb(i); if (a[i][st.top()] == a[i][j]) st.pop(); } st.push(j); } } vvvi row_fix(n, vvi(n)); rep2(i, 1, m - 1) { stack<int> st; rep(j, n) { while (!st.empty() and a[st.top()][i] < a[j][i]) { if (st.top() < j - 1) row_fix[st.top() + 1][j - 1].pb(i); st.pop(); } if (!st.empty()) { if (st.top() < j - 1) row_fix[st.top() + 1][j - 1].pb(i); if (a[st.top()][i] == a[j][i]) st.pop(); } st.push(j); } } // {bottom, right} -> {left, top} map<P, vp> mp; rep(i, m) rep(j, m) { int pre = -1, cnt = 0; for (int k : col_fix[i][j]) { if (pre + 1 < k) cnt = 0; cnt++; mp[{k, j}].eb(i, k - cnt + 1); pre = k; } } map<P, vp> rq; rep(i, n) rep(j, n) { int pre = -1, cnt = 0; for (int k : row_fix[i][j]) { if (pre + 1 < k) cnt = 0; cnt++; rq[{j, k}].eb(k - cnt + 1, i); pre = k; } } ll ans = 0; BIT cnt(n); for (auto &[p, v] : mp) { if (!rq.count(p)) continue; if (v.empty()) continue; vp &cur = rq[p]; // for (auto[i, j] : cur) { // for (auto[ni, nj] : v) { // if (i <= ni and nj <= j) ans++; // } // } sort(all(cur)); int it = cur.size() - 1; while (it >= 0 and cur[it].first > v.back().first) it--; rrep(i, v.size()) { cnt.add(v[i].second, 1); while (it >= 0 and (i == 0 or cur[it].first > v[i - 1].first)) { ans += cnt.sum(cur[it].second); it--; } } rep(i, v.size()) { cnt.add(v[i].second, -1); } } return ans; }
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