Submission #304000

#	Time	Username	Problem	Language	Result	Execution time	Memory
304000		Fdg	Packing Biscuits (IOI20_biscuits)	C++14	100 / 100	170 ms	1016 KiB

biscuits

#include <iostream>
#include <vector>
#include <map>
#include <set>
#include <algorithm>

using namespace std;

vector<long long> trans(const vector<long long>& a, long long sub) {
  vector<long long> na = a;
  na.pop_back();
  if (a.back() - sub > 1) {
    long long val = (a.back() - sub) / 2;
    if (na.size() == 0) na.push_back(val);
    else na.back() += val;
  }
  return na;
}

map<pair<int, long long>, long long> f;

long long solve(long long x, vector<long long> a, int pos) {
  if (a.size() == 0) return 1;
  if (f.count({pos, a.back()})) return f[{pos, a.back()}];

  long long ret = 0;
  if (a.back() >= x) {
    ret += solve(x, trans(a, x), pos + 1);
  }

  ret += solve(x, trans(a, 0), pos + 1);
  return f[{pos, a.back()}] = ret;
}

vector<long long> arr;

long long solve2(long long x, long long last, int pos) {
  if ((int) arr.size() <= pos && last < x) return 1;
  if (f.count({pos, last})) return f[{pos, last}];

  long long ret = 0;
  if (last >= x) {
    long long nlast = (pos + 1 < (int) arr.size() ? arr[pos + 1] : 0) + (last - x) / 2;
    ret += solve2(x, nlast, pos + 1);
  }

  long long nlast = (pos + 1 < (int) arr.size() ? arr[pos + 1] : 0) + last / 2;
  ret += solve2(x, nlast, pos + 1);
  return f[{pos, last}] = ret;
}

vector<long long> sums;

long long solve3(long long x, int pos, long long sub) {
  if (pos == -1) return sub == 0;
  if (f.count({pos, sub})) return f[{pos, sub}];

  long long cur = pos < (int) arr.size() ? arr[pos] : 0;

  long long ret = 0;
  if ((1LL << pos) <= (sums[pos] - sub) / x) {
    long long what = solve3(x, pos - 1, max(0LL, sub + x * (1LL << pos) - (1LL << pos) * cur));
    ret += what;
    if (what == (1LL << pos)) {
      ret += what;
      return f[{pos, sub}] = ret;
    }
  }

  ret += solve3(x, pos - 1, max(0LL, sub - (1LL << pos) * cur));

  return f[{pos, sub}] = ret;
}

long long count_tastiness(long long x, vector<long long> a) {
  f.clear(); sums.clear();

  // for (int i = 0; i < (int) a.size(); ++i) {
  //   if (a[i] > x) {
  //     long long add = (a[i] - x) / 2;
  //     a[i] = x + ((a[i] - x) & 1);
  //     if (i + 1 == (int) a.size())
  //       a.push_back(add);
  //     else
  //       a[i + 1] += add;
  //   }
  // }

  long long s = 0, pw = 1;
  for (int i = 0; i < 60; ++i) {
    if (i < (int) a.size())
      s += pw * a[i];
    pw <<= 1;
    sums.push_back(s);
  }

  // reverse(a.begin(), a.end());
  arr = a;
  // return solve2(x, arr[0], 0);
  // cout << "2: " << solve2(x, arr[0], 0) << endl;
  return solve3(x, 59, 0);
}

• Subtask 1: 9 / 9
• Subtask 2: 12 / 12
• Subtask 3: 21 / 21
• Subtask 4: 35 / 35
• Subtask 5: 23 / 23