Submission #435374

#	Time	Username	Problem	Language	Result	Execution time	Memory
435374		Collypso	Counting Mushrooms (IOI20_mushrooms)	C++17	0 / 100	21 ms	328 KiB

mushrooms

#include <bits/stdc++.h>
#define ll long long
#define ld long double
#define pii pair<int, int>
#define pll pair<ll, ll>
#define vt vector
#define pb push_back
#define all(x) (x).begin(), (x).end()
#define sz(x) (int) (x).size()
#pragma GCC optimize ("O3")
#pragma GCC optimize ("O2")
#define F first
#define S second
//#define endl '\n'
//#define int long long

using namespace std;

int use_machine(vt<int> x);

int subtask1(int n)
{
	int ans = 1;
    for(int i = 1; i < n; i++)
        if (use_machine({0, i}) == 0) ans++;
    return ans;
}

int group[20007];

int merge_group(int l, int r)
{
    if (r == l) return 0;
    vt<int> tmp(r - l + 1);
    for(int i = l; i <= r; i++) tmp[i - l] = i;
    int val = use_machine(tmp);

    if (val == r - l) return val;

    if (val == 0)
    {
        for(int i = l + 1; i <= r; i++) group[i] = l;
        return val;
    }

    int m = (l + r) / 2;
    int val1 = merge_group(l, m);
    int val2 = merge_group(m + 1, r);
    if (val1 + val2 == val) group[m + 1] = m;
    return val;
}

int count_mushrooms(int n)
{
    if (n <= 227) return subtask1(n);
    for(int i = 0; i < n; i++) group[i] = i;
    merge_group(0, n - 1);
    int sum = 1;
    for(int i = 1, cur = 1; i < n; i++)
    {
        if (group[i] != group[i - 1]) cur = !cur;
        sum += cur;
    }
    return sum;

    //for(int i = 0; i < n; i++) cout << group[i] << " ";
    //cout << endl;
}

• Subtask 1: 0 / 100