Submission #827559

#	Time	Username	Problem	Language	Result	Execution time	Memory
827559		NeroZein	Diversity (CEOI21_diversity)	C++17	38 / 100	23 ms	2388 KiB

diversity

#include "bits/stdc++.h"
using namespace std;
 
#ifdef Nero
#include "Deb.h"
#else
#define deb(...)
#endif

const int N = 3e5 + 5;

int a[N]; 
int freq[N];
bitset<N> se;
int cnt_freq[N];
long long prop_ps[N];

inline int64_t hilbertOrder(int x, int y, int pow, int rotate) {
  if (pow == 0) {
    return 0;
  }
  int hpow = 1 << (pow - 1);
  int seg = (x < hpow) ? ((y < hpow) ? 0 : 3) : ((y < hpow) ? 1 : 2);
  seg = (seg + rotate) & 3;
  const int rotateDelta[4] = {3, 0, 0, 1};
  int nx = x & (x ^ hpow), ny = y & (y ^ hpow);
  int nrot = (rotate + rotateDelta[seg]) & 3;
  int64_t subSquareSize = int64_t(1) << (2 * pow - 2);
  int64_t ans = seg * subSquareSize;
  int64_t add = hilbertOrder(nx, ny, pow - 1, nrot);
  ans += (seg == 1 || seg == 2) ? add : (subSquareSize - add - 1);
  return ans;
}

struct Query {
  int l, r, id; 
  int64_t ord;
  inline void calcOrder() {
    ord = hilbertOrder(l, r, 18, 0);
  }
};

inline bool operator<(const Query &x, const Query &y){
  return x.ord < y.ord;
}

void modify(int i, int v) {
  if (freq[a[i]]) {
    if (cnt_freq[freq[a[i]]] == 1) {
      se[freq[a[i]]] = 0;
    }
    cnt_freq[freq[a[i]]]--;
  }
  freq[a[i]] += v;
  if (freq[a[i]]) {
    cnt_freq[freq[a[i]]]++;
    if (cnt_freq[freq[a[i]]] == 1) {
      se[freq[a[i]]] = 1; 
    }
  }
}

vector<pair<int, int>> construct() {
  vector<pair<int, int>> left;
  vector<pair<int, int>> right;
  bool go_left = true;
  vector<int> xz;
  int cur_id = 0; 
  int tot = se.count(); 
  int cur_cnt = 0;
  while (cur_cnt < tot) {
    int next_id = se._Find_next(cur_id);
    xz.push_back(next_id);
    cur_id = next_id; 
    cur_cnt++; 
  }
  for (auto i : xz) {
    int x = cnt_freq[i] / 2;
    int y = cnt_freq[i] - x;
    if (cnt_freq[i] % 2 == 0) {
      left.push_back({i, x});
      right.push_back({i, x});
    } else {
      if (go_left) {
        left.push_back({i, y});
        if (x) {
          right.push_back({i, x});    
        }
      } else {
        if (x) {
          left.push_back({i, x});     
        }
        right.push_back({i, y}); 
      }
      go_left ^= 1;
    }
  }
  vector<pair<int, int>> ret = left; 
  reverse(right.begin(), right.end()); 
  for (auto [x, y] : right) {
    if (ret.back().first == x) {
      ret.back().second += y;
    } else {
      ret.push_back({x, y});      
    }
  }
  return ret;
}

long long prop(int x) {
  return (long long) x * (x + 1) / 2; 
}

long long get(vector<pair<int, int>> v) {
  long long ret = 0; 
  long long last = 0;
  long long normal_sum = 0;
  for (int i = (int) v.size() - 1; i >= 0; --i) {
    long long tmp = 0; 
    auto [element_freq, rep] = v[i];
    long long z = rep - 1; 
    tmp += (long long) element_freq * z * (z + 1) * (z + 2) / 6 * element_freq;
    tmp += last * element_freq * rep; 
    tmp += normal_sum * element_freq * rep * (rep + 1) / 2;
    last = (rep - 1) * rep / 2 * element_freq + last + normal_sum * rep;
    ret += tmp; 
    normal_sum += (long long) v[i].first * v[i].second; 
  }
  ret += prop(normal_sum); 
  return ret;
}

signed main() {
  ios::sync_with_stdio(false);
  cin.tie(nullptr);
  int n, q;
  cin >> n >> q;
  for (int i = 0; i < n; ++i) {
    cin >> a[i];
  }
  vector<Query> qs(q); 
  for (int i = 0; i < q; ++i) {
    int l, r;
    cin >> l >> r;
    --l, --r;
    qs[i].l = l, qs[i].r = r;
    qs[i].id = i;
    qs[i].calcOrder(); 
  }
  vector<long long> ans(q); 
  int l = 0, r = -1; 
  for (auto &pq : qs) {
    int ql = pq.l, qr = pq.r, id = pq.id;
    while (l > ql) modify(--l, 1);
    while (r < qr) modify(++r, 1);
    while (l < ql) modify(l++, -1);
    while (r > qr) modify(r--, -1); 
    vector<pair<int, int>> v = construct(); 
    ans[id] = get(v);
  }
  for (int i = 0; i < q; ++i) {
    cout << ans[i] << '\n';
  }
  return 0;
}

• Subtask 1: 4 / 4
• Subtask 2: 10 / 10
• Subtask 3: 8 / 8
• Subtask 4: 16 / 16
• Subtask 5: 0 / 26
• Subtask 6: 0 / 36