Submission #427413

#	Time	Username	Problem	Language	Result	Execution time	Memory
427413		peijar	Packing Biscuits (IOI20_biscuits)	C++17	100 / 100	119 ms	1304 KiB

biscuits

#include <bits/stdc++.h>
#define int long long
using namespace std;

#include "biscuits.h"

const int MAX = 101;
int dfs(const vector<int> &a, int nbRestants, int x, int curBit) {
  if (curBit == MAX)
    return 1;
  if (curBit < (int)a.size())
    nbRestants += a[curBit];
  else if (nbRestants < x)
    return 1;
  int sol = dfs(a, nbRestants / 2, x, curBit + 1);
  if (nbRestants >= x)
    sol += dfs(a, (nbRestants - x) / 2, x, curBit + 1);
  return sol;
}

using ll = __int128;

map<ll, int> dp;

void write(ll x) {
  if (x >= 10)
    write(x / 10);
  cout << (int)(x % 10);
}

int solve(ll n, const vector<int> &a, int x, const vector<ll> &prefixSum) {
  if (n <= 0)
    return 0;
  if (n == 1)
    return 1;
  if (dp.count(n))
    return dp[n];
  ll curPow = 1;
  int i = 0;
  while (2 * curPow < n) {
    curPow *= 2;
    i++;
  }
  int &ret = dp[n];
  ret = solve(curPow, a, x, prefixSum);
  ret += solve(min(n, 1 + prefixSum[i] / x) - curPow, a, x, prefixSum);
  return ret;
}

int count_tastiness(int x, vector<int> a) {
  while (a.size() < MAX)
    a.push_back(0);
  dp.clear();

  vector<ll> prefixSum(MAX);
  ll curPow = 1;
  for (int i = 0; i < MAX; ++i) {
    prefixSum[i] = (i ? prefixSum[i - 1] : 0) + curPow * a[i];
    curPow *= 2;
  }
  // dp(n) = nb de sol < n
  // si 2^i <= n < 2^n+1, alors
  // dp(n) = dp[2^i] + dp[min(2^n, s[i]/x-2^i + 1)]
  return solve(curPow / 2, a, x, prefixSum);
}

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