Submission #681666

#	Time	Username	Problem	Language	Result	Execution time	Memory
681666		evenvalue	Distributing Candies (IOI21_candies)	C++17	11 / 100	112 ms	13768 KiB

candies

#include "candies.h"
#include <bits/stdc++.h>
using namespace std;

template<typename T>
using min_heap = priority_queue<T, vector<T>, greater<T>>;
template<typename T>
using max_heap = priority_queue<T, vector<T>, less<T>>;

using int64 = long long;
using ld = long double;

constexpr int kInf = 1e9 + 10;
constexpr int64 kInf64 = 1e15 + 10;
constexpr int kMod = 1e9 + 7;

template<typename T>
class FenwickTree {
  size_t n;
  vector<T> bit;

public:
  explicit FenwickTree(const size_t N) : n(N), bit(N, T{}) {}
  explicit FenwickTree(const vector<T> &a) : FenwickTree(a.size()) {
    n = a.size();
    for (int i = 0; i < n; i++) {
      add(i, a[i]);
    }
  }

  [[nodiscard]] T sum(int r) const {
    T ans{};
    for (int i = r; i >= 0; i = (i & (i + 1)) - 1) {
      ans += bit[i];
    }
    return ans;
  }

  [[nodiscard]] T sum(const int l, const int r) const {
    return sum(r) - sum(l - 1);
  }

  void add(const int i, const T delta) {
    for (int j = i; j < n; j |= j + 1) {
      bit[j] += delta;
    }
  }
};

vector<int> subtask1(const vector<int> &C, const vector<int> &L, const vector<int> &R, const vector<int> &V) {
  const int n = C.size();
  const int q = L.size();
  vector<int> box(n);
  for (int query = 0; query < q; query++) {
    for (int i = L[query]; i <= R[query]; i++) {
      box[i] += V[query];
      box[i] = max(box[i], 0);
      box[i] = min(box[i], C[i]);
    }
  }
  return box;
}

vector<int> subtask2(const vector<int> &C, const vector<int> &L, const vector<int> &R, const vector<int> &V) {
  const int n = C.size();
  const int q = L.size();

  FenwickTree<int64> bit(n + 2);
  for (int i = 0; i < q; i++) {
    const int l = L[i] + 1, r = R[i] + 1, v = V[i];
    bit.add(l, v);
    bit.add(r + 1, -v);
  }

  vector<int> ans(n);
  for (int i = 1; i <= n; i++) {
    ans[i - 1] = (int) min(1LL * C[i - 1], bit.sum(i));
  }
  return ans;
}


vector<int> distribute_candies(vector<int> C, vector<int> L, vector<int> R, vector<int> V) {
  const int n = C.size();
  const int q = L.size();
  if (max(n, q) <= 2000) return subtask1(C, L, R, V);
  return subtask2(C, L, R, V);
}

Compilation message (stderr)

candies.cpp: In instantiation of 'void FenwickTree<T>::add(int, T) [with T = long long int]':
candies.cpp:71:17:   required from here
candies.cpp:44:23: warning: comparison of integer expressions of different signedness: 'int' and 'size_t' {aka 'long unsigned int'} [-Wsign-compare]
   44 |     for (int j = i; j < n; j |= j + 1) {
      |                     ~~^~~

• Subtask 1: 3 / 3
• Subtask 2: 8 / 8
• Subtask 3: 0 / 27
• Subtask 4: 0 / 29
• Subtask 5: 0 / 33