Submission #1181448

#	Time	Username	Problem	Language	Result	Execution time	Memory
1181448		jbareja	Rope (JOI17_rope)	C++20	100 / 100	696 ms	85144 KiB

rope

#include <bits/stdc++.h>

using namespace std;
using ll = long long;

int N; // liczba węzłów
int M; // liczba kolorów

vector<int> C;
vector<int> ans;
vector<int> cnt_color;

unordered_map<ll,int> M_1; // < posortowana para, ilość > - licząc od pierwszego
unordered_map<ll,int> M_2; // < posortowana para, ilość > - licząc od drugiego
vector<int> with_one_1;
vector<int> with_one_2;
vector<int> with_any_1;
vector<int> with_any_2;
int cnt_pairs_1 = 0;
int cnt_pairs_2 = 0;
int last1 = 0;
int first2 = 0;
int last2 = 0;

long long hsh_pair(int a, int b) {
	if (a > b) swap(a, b);
	return (ll)a + (ll)b * 1'000'007LL;
}

int cost(int a, int b) {
	int pairs_ab_1 = 0;
	if (M_1.contains(hsh_pair(a,b))) pairs_ab_1 = M_1[hsh_pair(a,b)];
	int cost1 = with_one_1[a] + with_one_1[b] - pairs_ab_1 + 2 * (cnt_pairs_1 - with_any_1[a] - with_any_1[b] + pairs_ab_1) + (last1 != a && last1 != b && last1 != 0);

	int pairs_ab_2 = 0;
	if (M_2.contains(hsh_pair(a,b))) pairs_ab_2 = M_2[hsh_pair(a,b)];
	int cost2 = with_one_2[a] + with_one_2[b] - pairs_ab_2 + 2 * (cnt_pairs_2 - with_any_2[a] - with_any_2[b] + pairs_ab_2) + (first2 != a && first2 != b && first2 != 0) + (last2 != a && last2 != b && last2 != 0);

	return min(cost1, cost2);
}

int cost_not_touching(int a, int b) {
	return N - cnt_color[a] - cnt_color[b];
}

bool is_touching(int a, int b) {
	if (M_1.contains(hsh_pair(a,b)) || M_2.contains(hsh_pair(a,b))) return true;
	if ((C[N-1] == a && C[N] == b) || (C[N-1] == b && C[N] == a)) return true;
	return false;
}

int main() {
	ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);

	cin >> N >> M;
	C.assign(N+2, 0);
	ans.assign(M+1, 0);
	cnt_color.assign(M+1, 0);
	with_one_1.assign(M+1, 0);
	with_one_2.assign(M+1, 0);
	with_any_1.assign(M+1, 0);
	with_any_2.assign(M+1, 0);

	vector<pair<int,int>> colors; // < -liczba wystąpień, kolor >

	for (int i=1; i<=N; i++) {
		cin >> C[i];
		cnt_color[C[i]]++;
	}

	for (int i=1; i<=M; i++) colors.push_back({ -cnt_color[i], i });
	sort(colors.begin(), colors.end());

	for (int i=1; i<=M; i++) ans[i] = N - cnt_color[i];

	for (int i=1; i+1<=N; i+=2) {
		M_1[hsh_pair( C[i], C[i+1] )]++;
		cnt_pairs_1++;
		if (C[i] == C[i+1]) with_any_1[C[i]]++;
		else with_one_1[C[i]]++, with_one_1[C[i+1]]++, with_any_1[C[i]]++, with_any_1[C[i+1]]++;
	}
	if (N % 2 == 1) last1 = C[N];

	first2 = C[1];
	for (int i=2; i+1<=N; i+=2) {
		M_2[hsh_pair( C[i], C[i+1] )]++;
		cnt_pairs_2++;
		if (C[i] == C[i+1]) with_any_2[C[i]] ++;
		else with_one_2[C[i]]++, with_one_2[C[i+1]]++, with_any_2[C[i]]++, with_any_2[C[i+1]]++;
	}
	if (N % 2 == 0) last2 = C[N];

	for (int i=1; i<=N-1; i++) if (C[i] != C[i+1]) {
		int temp = cost(C[i],C[i+1]);
		ans[C[i]] = min(ans[C[i]], temp);
		ans[C[i+1]] = min(ans[C[i+1]], temp);
	}

	for (int i=1; i<=M; i++) {
		for (const auto& [cnt, c]: colors) {
			if (i == c || is_touching(i, c)) continue;
			int temp = cost_not_touching(i, c);
			ans[i] = min(ans[i], temp);
			ans[c] = min(ans[c], temp);
			break;
		}
	}

	for (int i=1; i<=M; i++) cout << ans[i] << '\n';
}

• Subtask 1: 15 / 15
• Subtask 2: 30 / 30
• Subtask 3: 10 / 10
• Subtask 4: 25 / 25
• Subtask 5: 20 / 20