Submission #143509

#TimeUsernameProblemLanguageResultExecution timeMemory
143509imeimi2000Rectangles (IOI19_rect)C++17
0 / 100
137 ms101252 KiB
#include "rect.h" #include <vector> #include <set> using namespace std; typedef long long llong; const int inf = 1e8; int n, m; int L[2501][2501]; int R[2501][2501]; int U[2501][2501]; int D[2501][2501]; int Lm[2501][2501]; int Rm[2501][2501]; int Um[2501][2501]; int Dm[2501][2501]; struct idxtree { const static int sz = 1 << 12; int seg[sz << 1]; void init(vector<int> v) { for (int i = 1; i <= v.size(); ++i) seg[i + sz] = v[i - 1]; for (int i = sz; i--; ) seg[i] = min(seg[i << 1], seg[i << 1 | 1]); } int query(int x, int y) { x += sz; y += sz; int ret = inf; while (x <= y) { if ((x & 1) == 1) ret = min(ret, seg[x++]); if ((y & 1) == 0) ret = min(ret, seg[y--]); x >>= 1; y >>= 1; } return ret; } } Li[2501], Ri[2501], Ui[2501], Di[2501]; llong count_rectangles(vector<vector<int>> a) { n = a.size(); m = a[0].size(); //step 1 for (int i = 1; i <= n; ++i) { vector<int> st; st.push_back(0); for (int j = 1; j <= m; ++j) { while (st.size() > 1 && a[i - 1][st.back() - 1] <= a[i - 1][j - 1]) st.pop_back(); L[i][j] = st.back(); st.push_back(j); } } for (int i = 1; i <= n; ++i) { vector<int> st; st.push_back(m + 1); for (int j = m; j > 0; --j) { while (st.size() > 1 && a[i - 1][st.back() - 1] <= a[i - 1][j - 1]) st.pop_back(); R[i][j] = st.back(); st.push_back(j); } } for (int i = 1; i <= m; ++i) { vector<int> st; st.push_back(0); for (int j = 1; j <= n; ++j) { while (st.size() > 1 && a[st.back() - 1][i - 1] <= a[j - 1][i - 1]) st.pop_back(); U[j][i] = st.back(); st.push_back(j); } } for (int i = 1; i <= m; ++i) { vector<int> st; st.push_back(n + 1); for (int j = n; j > 0; --j) { while (st.size() > 1 && a[st.back() - 1][i - 1] <= a[j - 1][i - 1]) st.pop_back(); D[j][i] = st.back(); st.push_back(j); } } //step 2 for (int i = 1; i <= n; ++i) { vector<int> st; st.push_back(0); for (int j = 1; j <= m; ++j) { while (st.size() > 1 && a[i - 1][st.back() - 1] < a[i - 1][j - 1]) st.pop_back(); Lm[i][j] = st.back(); st.push_back(j); } } for (int i = 1; i <= n; ++i) { vector<int> st; st.push_back(m + 1); for (int j = m; j > 0; --j) { while (st.size() > 1 && a[i - 1][st.back() - 1] < a[i - 1][j - 1]) st.pop_back(); Rm[i][j] = st.back(); st.push_back(j); } } for (int i = 1; i <= m; ++i) { vector<int> st; st.push_back(0); for (int j = 1; j <= n; ++j) { while (st.size() > 1 && a[st.back() - 1][i - 1] < a[j - 1][i - 1]) st.pop_back(); Um[j][i] = st.back(); st.push_back(j); } } for (int i = 1; i <= m; ++i) { vector<int> st; st.push_back(n + 1); for (int j = n; j > 0; --j) { while (st.size() > 1 && a[st.back() - 1][i - 1] < a[j - 1][i - 1]) st.pop_back(); Dm[j][i] = st.back(); st.push_back(j); } } //step 3 for (int i = 1; i <= m; ++i) { vector<int> Ls, Rs; for (int j = 1; j <= n; ++j) { Ls.push_back(Lm[j][i]); Rs.push_back(Rm[j][i]); } Li[i].init(Ls); Ri[i].init(Rs); } for (int i = 1; i <= n; ++i) { vector<int> Us, Ds; for (int j = 1; j <= m; ++j) { Us.push_back(Um[i][j]); Ds.push_back(Dm[i][j]); } Ui[i].init(Us); Di[i].init(Ds); } int ans = 0; set<llong> sp; for (int i = 2; i < n; ++i) { for (int j = 2; j < m; ++j) { int Lx = L[i][j] + 1; if (Lx == 1) continue; int Rx = R[i][j] - 1; if (Rx == m) continue; int Ux = U[i][j] + 1; if (Ux == 1) continue; int Dx = D[i][j] - 1; if (Dx == n) continue; llong idx = ((llong)(Lx << 12 | Rx)) << 24 | (Ux << 12 | Dx); if (sp.count(idx)) continue; sp.insert(idx); if (Ri[Lx - 1].query(Ux, Dx) - 1 < Rx) continue; if (Li[Rx + 1].query(Ux, Dx) + 1 > Lx) continue; if (Di[Ux - 1].query(Lx, Rx) - 1 < Dx) continue; if (Ui[Dx + 1].query(Lx, Rx) + 1 > Ux) continue; ++ans; } } return ans; }

Compilation message (stderr)

rect.cpp: In member function 'void idxtree::init(std::vector<int>)':
rect.cpp:23:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
         for (int i = 1; i <= v.size(); ++i) seg[i + sz] = v[i - 1];
                         ~~^~~~~~~~~~~
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