Submission #1318003

#	Time	Username	Problem	Language	Result	Execution time	Memory
1318003		windowwife	Triple Peaks (IOI25_triples)	C++20	100 / 100	1216 ms	24332 KiB

triples

#ifndef rtgsp
#include "triples.h"
#endif // rtgsp

#include<bits/stdc++.h>
#define ll long long
#define task ""
using namespace std;
const int maxn = 2e5 + 2;
int n, h[maxn], res, row[maxn], col[maxn];
vector<int> cr, cc, r[maxn], c[maxn];

ll count_triples(vector<int> H)
{
    res = 0; cr.clear(); cc.clear();
    n = (int)H.size();
    for (int i = 0; i < n; i++)
    {
        h[i] = H[i];
        r[i].clear();
        c[i].clear();
        cr.push_back(h[i] - i);
        cc.push_back(h[i] + i);
    }
    sort(cr.begin(), cr.end());
    cr.resize(unique(cr.begin(), cr.end()) - cr.begin());
    sort(cc.begin(), cc.end());
    cc.resize(unique(cc.begin(), cc.end()) - cc.begin());
    for (int i = 0; i < n; i++)
    {
        int x = lower_bound(cr.begin(), cr.end(), h[i] - i) - cr.begin();
        r[x].push_back(i);
        row[i] = x;
    }
    for (int i = n - 1; i >= 0; i--)
    {
        int x = lower_bound(cc.begin(), cc.end(), h[i] + i) - cc.begin();
        c[x].push_back(i);
        col[i] = x;
    }
    for (int i = 0; i < n - 2; i++)
    {
        int k = h[i] + i;
        if (k < n)
        {
            int j = k - h[k];
            if (j > i && h[j] == j - i) res++;
            if (h[k] + i != k - h[k])
            {
                j = h[k] + i;
                if (j < k && h[j] == k - j) res++;
            }
        }
        int j = h[i] + i;
        if (j < n - 1)
        {
            int k = h[j] + i;
            if (k > j && k < n && h[k] == k - j) res++;
        }
    }
    for (int k = 2; k < n; k++)
    {
        int i = k - h[k];
        if (i >= 0)
        {
            int j = h[i] + i;
            if (j < k && h[j] == k - j) res++;
            if (k - h[i] != h[i] + i)
            {
                j = k - h[i];
                if (j > i && h[j] == j - i) res++;
            }
        }
    }
    for (int j = 1; j < n - 1; j++)
    {
        if (r[row[j]].size() < c[col[j]].size())
        {
            for (int i : r[row[j]])
            {
                if (i == j) break;
                int k = h[i] + j;
                if (k < n && h[j] == k - i && h[k] == j - i && h[k] != k - j) res++;
            }
        }
        else
        {
            for (int k : c[col[j]])
            {
                if (k == j) break;
                int i = j - h[k];
                if (i >= 0 && h[i] == k - j && h[i] != j - i && h[j] == k - i) res++;
            }
        }
    }
    return res;
}

ll randint (ll l, ll r)
{
	ll res = 0;
	for (int i = 0; i < 4; i++) res = (res << 15) ^ (rand() & ((1 << 15) - 1));
	return l + res % (r - l + 1);
}

vector<int> ans, even;

vector<int> construct_range(int M, int K)
{
	ans.resize(M, 0);
	int seed = 0;
	while (true)
	{
		mt19937 rd(seed);
		even.clear();
		for (int d = 0; d <= M; d += 2) even.push_back(d);
		shuffle(even.begin(), even.end(), rd);
		for (int i = 0; i < M; i++) ans[i] = 0;
		for (int i = 1; i < (int)min(14000, (int)even.size()); i++)
		{
			for (int j = 0; j < i; j++)
			{
				if (ans[(even[i] + even[j])/2] == 0)
				{
					ans[(even[i] + even[j])/2] = abs(even[i] - even[j])/2;
				}
			}
		}
		for (int i = 0; i < M; i++)
			if (ans[i] == 0) ans[i] = 1;
		int cnt = count_triples(ans);
		cerr << "seed = " << seed << '\n';
		cerr << "peaks = " << cnt << '\n';
		cerr << "score = " << min((long double)1, (long double)cnt/K) << '\n';
		if (cnt >= K) break;
		++seed;
	}
	return ans;
}

#ifdef rtgsp
int main()
{
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);
    /*string s;
    int N;
    vector<int> H;
    H.clear();
    cin >> s >> N >> N;
    for (int i = 0; i < N; i++)
    {
        int x;
        cin >> x;
        H.push_back(x);
    }
    cout << count_triples(H);*/
    int M = 500, K = 30;
    cin >> M >> K;
	auto v = construct_range(M, K);
	cout << v.size() << '\n';
	for (int x : v) cout << x << " ";
}
#endif // rtgsp

• Subtask 0: 0 / 0
• Subtask 1: 8 / 8
• Subtask 2: 6 / 6
• Subtask 3: 10 / 10
• Subtask 4: 11 / 11
• Subtask 5: 16 / 16
• Subtask 6: 19 / 19
• Subtask 7: 5 / 5
• Subtask 8: 5 / 5
• Subtask 9: 5 / 5
• Subtask 10: 5 / 5
• Subtask 11: 5 / 5
• Subtask 12: 5 / 5