Submission #501091

#	Time	Username	Problem	Language	Result	Execution time	Memory
501091		600Mihnea	Pairs (IOI07_pairs)	C++17	52 / 100	4027 ms	210356 KiB

pairs

#include <bits/stdc++.h>

using namespace std;

typedef long long ll;

signed main() {
  ios::sync_with_stdio(0); cin.tie(0);

 // freopen ("input", "r", stdin);

  int B;
  cin >> B;
  ///assert(B == 1 || B == 2 || B == 3);

  if (B == 1) {
    int n, d, _;
    cin >> n >> d >> _;
    vector<int> a(n);
    for (auto &x : a) {
      cin >> x;
    }
    sort(a.begin(), a.end());
    ll sol = 0;
    int C = 0, c = 0;
    for (int i = 0; i < n; i++) {
      int low = a[i] - d, high = a[i] + d;
      while (C < n && a[C] <= high) {
        C++;
      }
      while (c < n && a[c] < low) {
        c++;
      }
      sol += C - c;
    }
    sol -= n;
    sol /= 2;
    cout << sol << "\n";
    exit(0);
  }
  if (B == 2) {
    /// aib 2d
    int n, d, L;
    cin >> n >> d >> L;
    L *= 2;
    vector<map<int, int>> guys(L + 1);
    vector<vector<int>> aib(L + 1);


    function<void(int, int)> prep_get = [&] (int a, int b) {
      if (a < 0) a = 0;
      if (b < 0) b = 0;
      if (a > L) a = L;
      if (b > L) b = L;
      if (!a || !b) return;
      int sol = 0;
      for (int i = a; i >= 1; i -= i & (-i)) {
        guys[i][b] = 0;
      }
    };

    function<void(int, int, int)> prep_add = [&] (int a, int b, int x) {
      assert(1 <= a && a <= L);
      assert(1 <= b && b <= L);
      for (int i = a; i <= L; i += i & (-i)) {
        guys[i][b] = 0;
      }
    };

    function<int(int, int)> get = [&] (int a, int b) {
      if (a < 0) a = 0;
      if (b < 0) b = 0;
      if (a > L) a = L;
      if (b > L) b = L;
      if (!a || !b) return 0;
      int sol = 0;
      for (int i = a; i >= 1; i -= i & (-i)) {
        assert(guys[i].count(b));
        for (int j = guys[i][b]; j >= 1; j -= j & (-j)) {
          sol += aib[i][j];
        }
      }
      return sol;
    };

    function<void(int, int, int)> add = [&] (int a, int b, int x) {
      assert(1 <= a && a <= L);
      assert(1 <= b && b <= L);
      for (int i = a; i <= L; i += i & (-i)) {
        assert(guys[i].count(b));

        for (int j = guys[i][b]; j < (int) aib[i].size(); j += j & (-j)) {
          aib[i][j] += x;
        }
      }
    };

    vector<int> x(n), y(n);
    for (int i = 0; i < n; i++) {
      int xx, yy;
      cin >> xx >> yy;
      x[i] = xx + yy;
      y[i] = xx - yy + L / 2;
      prep_add(x[i], y[i], 1);
      prep_get(x[i] + d, y[i] + d);
      prep_get(x[i] - d - 1, y[i] + d);
      prep_get(x[i] + d, y[i] - d - 1);
      prep_get(x[i] - d - 1, y[i] - d - 1);
    }
    for (int i = 0; i <= L; i++) {
      int cur = 0;
      for (auto &it : guys[i]) {
        cur++;
        it.second = cur;
      }
      aib[i].resize(cur + 1);
    }

    for (int i = 0; i < n; i++) {
      add(x[i], y[i], 1);
    }


    ll sol = 0;
    for (int i = 0; i < n; i++) {
      sol += get(x[i] + d, y[i] + d) - get(x[i] - d - 1, y[i] + d) - get(x[i] + d, y[i] - d - 1) + get(x[i] - d - 1, y[i] - d - 1);
    }
    sol -= n;
    sol /= 2;
    cout << sol << "\n";
    exit(0);
  }
  assert(0);

  return 0;
}

Compilation message (stderr)

pairs.cpp: In lambda function:
pairs.cpp:56:11: warning: unused variable 'sol' [-Wunused-variable]
   56 |       int sol = 0;
      |           ^~~

• Subtask 1: 6 / 6
• Subtask 2: 6 / 6
• Subtask 3: 6 / 6
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