Submission #205724

#	Time	Username	Problem	Language	Result	Execution time	Memory
205724		ADJA	Rectangles (IOI19_rect)	C++14	72 / 100	5070 ms	303692 KiB

rect

#include "rect.h"
 
#include <iostream>
#include <cstdio>
#include <cstdlib>
#include <vector>
#include <set>
#include <map>
#include <algorithm>
#include <bitset>
#include <cmath>
#include <queue>
#include <stack>
#include <string>
 
#define sz(x) (int) x.size()
#define all(x) x.begin(), x.end()
 
using namespace std;

const int MAXN = 2550;

class Fenwick {
private:
  vector <long long> f;
public:
  void init(int n) {
    f.assign(n, 0);
  }
  void update(int pos, int delta) {
    for (; pos < sz(f); pos = (pos | (pos + 1))) {
      f[pos] += delta;
    }
  }
  long long sum(int pos) {
    long long res = 0;
    for (; pos >= 0; pos = (pos & (pos + 1)) - 1) {
      res += f[pos];
    }
    return res;
  }
  long long sum(int l, int r) {
    return sum(r) - sum(l - 1);
  }
};

struct Segment {
  int r, from, to, len;
};

bool cmpFromToR(Segment &a, Segment &b) {
  // pair<pair<int, int>, int> ap = {{a.from, a.to}, a.r};
  // pair<pair<int, int>, int> bp = {{b.from, b.to}, b.r};
  // return ap < bp;
  if (a.from != b.from) {
    return a.from < b.from;
  }
  if (a.to != b.to) {
    return a.to < b.to;
  }
  return a.r < b.r;
}

bool cmpRToLen(Segment &a, Segment &b) {
  // pair<pair<int, int>, int> ap = {{a.r, a.to}, a.len};
  // pair<pair<int, int>, int> bp = {{b.r, b.to}, b.len};
  // return ap < bp;
  if (a.r != b.r) {
    return a.r < b.r;
  }
  if (a.to != b.to) {
    return a.to < b.to;
  }
  return a.len < b.len;
}

bool cmpToRFrom(Segment &a, Segment &b) {
  // pair<pair<int, int>, int> ap = {{a.to, a.r}, -a.from};
  // pair<pair<int, int>, int> bp = {{b.to, b.r}, -b.from};
  // return ap < bp;
  if (a.to != b.to) {
    return a.to < b.to;
  }
  if (a.r != b.r) {
    return a.r < b.r;
  }
  return -a.from < -b.from;
}

int n, m;
int a[MAXN][MAXN];
vector<Segment> rows, cols;
Fenwick f;

void initRowsAndCols() {
  for (int i = 1; i + 1 < n; i++) {
    stack <int> st;
    for (int j = 0; j < m; j++) {
      while (!st.empty() && a[i][st.top()] < a[i][j]) {
        st.pop();
      }
      if (!st.empty() && st.top() + 1 < j) {
        rows.push_back({i, st.top(), j, 1});
      }
      st.push(j);
    }
    while (!st.empty()) {
      st.pop();
    }
    for (int j = m - 1; j >= 0; j--) {
      while (!st.empty() && a[i][st.top()] < a[i][j]) {
        st.pop();
      }
      if (!st.empty() && a[i][st.top()] != a[i][j] && j + 1 < st.top()) {
        rows.push_back({i, j, st.top(), 1});
      }
      st.push(j);
    }
  }

  for (int j = 1; j + 1 < m; j++) {
    stack <int> st;
    for (int i = 0; i < n; i++) {
      while (!st.empty() && a[st.top()][j] < a[i][j]) {
        st.pop();
      }
      if (!st.empty() && st.top() + 1 < i) {
        cols.push_back({j, st.top(), i, 1});
      }
      st.push(i);
    }
    while (!st.empty()) {
      st.pop();
    }
    for (int i = n - 1; i >= 0; i--) {
      while (!st.empty() && a[st.top()][j] < a[i][j]) {
        st.pop();
      }
      if (!st.empty() && a[st.top()][j] != a[i][j] && i + 1 < st.top()) {
        cols.push_back({j, i, st.top(), 1});
      }
      st.push(i);
    }
  }
}

void calcLen() {
  sort(all(rows), cmpFromToR);
  for (int i = 0; i < sz(rows); i++) {
    if (i > 0 && rows[i - 1].from == rows[i].from && rows[i - 1].to == rows[i].to 
        && rows[i - 1].r + 1 == rows[i].r) {
      rows[i].len = rows[i - 1].len + 1;
    }
  }

  sort(all(cols), cmpFromToR);
  for (int i = 0; i < sz(cols); i++) {
    if (i > 0 && cols[i - 1].from == cols[i].from && cols[i - 1].to == cols[i].to 
        && cols[i - 1].r + 1 == cols[i].r) {
      cols[i].len = cols[i - 1].len + 1;
    }
  }
}

void printSegment(Segment &a) {
  cerr << a.r << " " << a.from << " " << a.to << " " << a.len << endl;
}

long long count_rectangles(std::vector<std::vector<int> > A) {
  n = sz(A); m = sz(A[0]);
  for (int i = 0; i < n; i++) {
    for (int j = 0; j < m; j++) {
      a[i][j] = A[i][j];
    }
  }

  initRowsAndCols();
  calcLen();

  f.init(m);

  sort(all(rows), cmpRToLen);
  sort(all(cols), cmpToRFrom);

  /* for (int i = 0; i < sz(rows); i++) {
    printSegment(rows[i]);
  }
  cerr << "Cols:" << endl;
  for (int i = 0; i < sz(cols); i++) {
    printSegment(cols[i]);
  }
  cerr << endl; */

  long long ans = 0;

  vector<int> curRows;
  vector<int> curCols;
  int pRows = 0, pCols = 0;
  for (int i = 1; i + 1 < n; i++) {
    for (int j = 1; j + 1 < m; j++) {
      while (pRows < sz(rows) && rows[pRows].r == i && rows[pRows].to == j + 1) {
        curRows.push_back(pRows);
        pRows++;
      }
      while (pCols < sz(cols) && cols[pCols].to == i + 1 && cols[pCols].r == j) {
        curCols.push_back(pCols);
        pCols++;
      }

      // cerr << i << " " << j << " " << sz(curRows) << " " << sz(curCols) << endl;

      int curColsP = 0;
      for (auto &row : curRows) {
        while (curColsP < sz(curCols) && cols[curCols[curColsP]].from >= i - rows[row].len) {
          f.update(j - cols[curCols[curColsP]].len + 1, 1);
          curColsP++;
        }
        ans += f.sum(0, rows[row].from + 1);
      }

      for (int k = 0; k < curColsP; k++) {
        f.update(j - cols[curCols[k]].len + 1, -1);
      }
      curRows.clear();
      curCols.clear();
    }
  }

  return ans;
}

• Subtask 1: 8 / 8
• Subtask 2: 7 / 7
• Subtask 3: 12 / 12
• Subtask 4: 22 / 22
• Subtask 5: 10 / 10
• Subtask 6: 13 / 13
• Subtask 7: 0 / 28