Submission #434158

#	Time	Username	Problem	Language	Result	Execution time	Memory
434158		krist7599555	Jelly Flavours (IOI20_jelly)	C++17	100 / 100	107 ms	456 KiB

jelly

#include <algorithm>
#include <cassert>
#include <cstring>
#include <vector>
#include <numeric>
#include <iostream>
#include <tuple>
typedef std::vector<int> Vec;
typedef std::pair<int, int> Pii;
#define rep(i,a,b) for(auto i = a; i != b; ++i)
 
const int MN = 2e3+10;
const int MV = 1e4+10;
 
struct Data {
	public:
		int jelly_count, remain_b;
    Data(int cnt, int rem): jelly_count(cnt), remain_b(rem) {}
		Data increase_jelly_count() {return {jelly_count+1, remain_b};}
		Data buy_b(int cost) { return {jelly_count+1, remain_b - cost};}
		bool operator < (const Data& o) const {
      return std::tie(jelly_count, remain_b) < std::tie(o.jelly_count, o.remain_b);
    }
};
 
int find_maximum_unique(int x_total, int y_total, std::vector<int> an, std::vector<int> bn) {
  std::vector<Data> dp(x_total+1, Data(0, 0)); // dp[i] = how many jelly count can do when `remain x` == i
  dp[x_total] = Data(0, y_total);
 
	std::vector<int> ord(an.size());
	std::iota(ord.begin(), ord.end(), 0); // 0 1 2 3 4 5 6 7
	std::sort(ord.begin(), ord.end(), [&](int u, int v){ return bn[u] < bn[v]; }); // sort by `b`

	for (int i : ord) {
		int curr_a = an[i]; // a = ? ? ? ? ?
		int curr_b = bn[i]; // b = 1 2 3 4 5 
		for(int remain_a = 0; remain_a <= x_total; ++remain_a) {
      dp[remain_a] = std::max({
        // case 1: not neither buy from `a` or `b`
        dp[remain_a],
        // case 2: buy from `b` greedy 
        curr_b <= dp[remain_a].remain_b 
          ? dp[remain_a].buy_b(curr_b) // greedy by `b` if possible
          : dp[remain_a],
        // case 3: buy from `a` dynamic programing
        curr_a + remain_a <= x_total
          ? dp[remain_a + curr_a].increase_jelly_count() // dynamic programming on `a` 
          : dp[remain_a]
      });
		}
	}
	return std::max_element(dp.begin(), dp.end())->jelly_count; // dp[0].jelly_count
}

inline int input() {
  int i; std::cin >> i; return i;
}

#ifdef KRIST_LOCAL

int main() {
  assert(4 == find_maximum_unique(6, 12, Vec({5, 1, 5, 6, 3}), Vec({3, 5, 4, 6, 7})));
  puts("pass");
  // using namespace std;
  // cin.sync_with_stdio(0);
  // int n = input();
  // int x = input();
  // int y = input();
  // std::vector<int> xn(n);
  // std::vector<int> yn(n);
  // rep(i, 0, n) xn[i] = input();
  // rep(i, 0, n) yn[i] = input();
  // cout << find_maximum_unique(x, y, xn, yn);
}

#endif

• Subtask 1: 11 / 11
• Subtask 2: 24 / 24
• Subtask 3: 9 / 9
• Subtask 4: 10 / 10
• Subtask 5: 14 / 14
• Subtask 6: 32 / 32