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Submission #1080495

# Submission time Handle Problem Language Result Execution time Memory
1080495 2024-08-29T10:28:29 Z Joshua_Andersson Simurgh (IOI17_simurgh) C++14
13 / 100
 116 ms 6820 KB 
#include "simurgh.h"

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

typedef long long ll;
const ll linf = ll(1e18);

typedef vector<int> vi;
typedef vector<vi> vvi;
typedef pair<int, int> p2;

#define rep(i, high) for (int i = 0; i < high; i++)
#define repp(i, low, high) for (int i = low; i < high; i++)
#define repe(i, container) for (auto& i : container)
#define sz(container) ((int)container.size())
#define all(x) begin(x),end(x)

#if _LOCAL
#define assert(x) if (!(x)) __debugbreak()
#endif

struct UF
{
	vi par;
	UF(int n) : par(n)
	{
		rep(i, n)par[i] = i;
	}
	int find(int x) { return x == par[x] ? x : par[x] = find(par[x]); }
	void merge(int a, int b)
	{
		a = find(a); b = find(b);
		if (a == b) return;
		par[b] = a;
	}
};

vi spanning;
const int maxn = 500;
const int maxm = maxn * maxn;
int is_golden[maxm], vis[maxn], parnode[maxn], paredge[maxn];
int depth[maxn], visedge[maxm], maxup[maxn];

vector<p2> up_edges[maxn];
void dfs(int u, vector<vector<p2>>& edges)
{
	depth[u] = depth[parnode[u]] + 1;
	repe(e, edges[u])
	{
		if (vis[e.first]) // back edge
		{
			if (visedge[e.second]) continue;
			visedge[e.second] = 1;
			up_edges[u].push_back(e);
			maxup[u] = min(maxup[u], depth[e.first]);
		}
		else
		{
			assert(!visedge[e.second]);
			visedge[e.second] = 1;
			spanning.push_back(e.second);
			vis[e.first] = 1;
			parnode[e.first] = u;
			paredge[e.first] = e.second;
			dfs(e.first, edges);
			maxup[u] = min(maxup[u], maxup[e.first]);
			if (maxup[u]>depth[u]) // bridge
			{
				is_golden[e.second] = 1;
			}
		}
	}
}

vi a, b;
int n;
int forest_query(vi edges)
{
	vi q;
	UF uf(n);
	repe(u, edges)
	{
		q.emplace_back(u);
		if (uf.find(a[u]) == uf.find(b[u])) assert(0);
		uf.merge(a[u], b[u]);
	}
	int num_good = 0;
	repe(s, spanning)
	{
		if (uf.find(a[s]) == uf.find(b[s])) continue;
		uf.merge(a[s], b[s]);
		num_good += is_golden[s];
		q.push_back(s);
	}
	assert(sz(q) < n);
	return count_common_roads(q) - num_good;
}

std::vector<int> find_roads(int N, std::vector<int> A, std::vector<int> B) {
	a = A;
	b = B;
	n = N;
	rep(i, maxn) maxup[i] = int(1e6);
	memset(is_golden, 0, sizeof(is_golden));
	memset(parnode, -1, sizeof(parnode));
	if (n==2)
	{
		return { 0 };
	}
	int m = sz(a);

	vector<vector<p2>> dedges(n);
	rep(i, m)
	{
		dedges[a[i]].emplace_back(b[i], i);
		dedges[b[i]].emplace_back(a[i], i);
	}
	vis[0] = 1;
	parnode[0] = 0;
	depth[0] = 0;
	dfs(0, dedges);
	parnode[0] = -1;
	repp(u, 1, n)
	{
		repe(e, up_edges[u])
		{
			vi cycle = { e.second };

			int v = u;
			while (v != 0 && v != e.first)
			{
				cycle.push_back(paredge[v]);
				v = parnode[v];
			}

			int mx = 0;
			vector<p2> res;
			rep(i, sz(cycle))
			{
				UF uf(n);
				vi q;
				rep(j, sz(cycle))
				{
					if (i == j) continue;
					q.push_back(cycle[j]);
					uf.merge(a[cycle[j]], b[cycle[j]]);
				}
				repe(u, spanning)
				{
					if (uf.find(a[u]) == uf.find(b[u])) continue;
					uf.merge(a[u], b[u]);
					q.push_back(u);
				}
				res.emplace_back(cycle[i], count_common_roads(q));
				mx = max(mx, res.back().second);
			}
			
			repe(v, res)
			{
				if (v.second < mx)
				{
					is_golden[v.first] = 1;
				}
			}

		}
	}
	
	assert(sz(spanning) == n - 1);
	//vi q(n - 1);
	//rep(i, n-1)
	//{
	//	int eind = spanning[i].first;
	//	vi trongle;
	//	int u = a[eind];
	//	int v = b[eind];

	//	trongle.push_back(eind);
	//	repe(e, adj[u])
	//	{
	//		if (e != eind)
	//		{
	//			trongle.push_back(e);
	//			break;
	//		}
	//	}
	//	if (sz(trongle)==1)
	//	{
	//		repe(e, adj[v])
	//		{
	//			if (e != eind)
	//			{
	//				trongle.push_back(e);
	//				break;
	//			}
	//		}
	//	}
	//	
	//	set<int> nodes;
	//	nodes.insert(a[trongle[0]]);
	//	nodes.insert(b[trongle[0]]);
	//	nodes.insert(a[trongle[1]]);
	//	nodes.insert(b[trongle[1]]);
	//	trongle = vi();
	//	
	//	rep(j, m)
	//	{
	//		if (nodes.find(a[j])!=nodes.end()&&nodes.find(b[j])!=nodes.end())
	//		{
	//			trongle.push_back(j);
	//		}
	//	}

	//	UF uf(n);
	//	uf.merge(a[trongle[0]], b[trongle[0]]);
	//	uf.merge(a[trongle[1]], b[trongle[1]]);
	//	uf.merge(a[trongle[2]], b[trongle[2]]);
	//	vi sp;
	//	rep(e, m)
	//	{
	//		if (uf.find(a[e]) == uf.find(b[e])) continue;
	//		uf.merge(a[e], b[e]);
	//		sp.push_back(e);
	//	}

	//	int m = 0;
	//	vector<p2> res;
	//	rep(j, 3)
	//	{
	//		vi q;
	//		rep(k, 3)
	//		{
	//			if (j == k) continue;
	//			q.push_back(trongle[k]);
	//		}
	//		repe(s, sp) q.push_back(s);
	//		
	//		int r = count_common_roads(q);
	//		m = max(m, r);
	//		res.emplace_back(trongle[j], r);
	//	}
	//	rep(j, 3)
	//	{
	//		if (res[j].first == eind)
	//		{
	//			spanning[i].second = res[j].second < m;
	//			break;
	//		}
	//	}
	//}

	vector<set<int>> edges(n);
	rep(i, m)
	{
		edges[a[i]].insert(i);
		edges[b[i]].insert(i);
	}
	queue<int> leaf;
	vi deg(n);
	rep(i, n)
	{
		deg[i] = forest_query(vi(all(edges[i])));
		if (deg[i] == 1) leaf.push(i);
	}

	vi par(n, -1);
	while (sz(leaf))
	{
		int u = leaf.front();
		leaf.pop();

		if (deg[u] == 0) break;
		assert(deg[u] == 1);
		int lo = -1;
		int hi = sz(edges[u]);
		while (lo+1<hi)
		{
			int mid = (lo + hi) / 2;
			vi q;
			auto start = edges[u].begin();
			rep(i, mid + 1)
			{
				q.push_back(*start);
				start++;
			}
			if (forest_query(q))
			{
				hi = mid;
			}
			else lo = mid;
		}
		auto start = edges[u].begin();
		rep(i, hi) start = next(start);
		int e = *start;
		int v = a[e] == u ? b[e] : a[e];
		edges[v].erase(e);
		deg[v]--;
		if (deg[v]==1)
		{
			leaf.push(v);
		}
		par[u] = e;
	}

	vi r;
	rep(i, n) if (par[i] != -1)r.push_back(par[i]);
	int common = count_common_roads(r);
	assert(common == n - 1);
	return r;
}

Subtask #1
13.0 / 13.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 1368 KB correct
2 Correct 1 ms 1372 KB correct
3 Correct 1 ms 1372 KB correct
4 Correct 1 ms 1372 KB correct
5 Correct 1 ms 1372 KB correct
6 Correct 1 ms 1372 KB correct
7 Correct 1 ms 1372 KB correct
8 Correct 1 ms 1372 KB correct
9 Correct 1 ms 1372 KB correct
10 Correct 1 ms 1372 KB correct
11 Correct 1 ms 1372 KB correct
12 Correct 1 ms 1372 KB correct
13 Correct 1 ms 1372 KB correct

Subtask #2
0 / 17.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 1368 KB correct
2 Correct 1 ms 1372 KB correct
3 Correct 1 ms 1372 KB correct
4 Correct 1 ms 1372 KB correct
5 Correct 1 ms 1372 KB correct
6 Correct 1 ms 1372 KB correct
7 Correct 1 ms 1372 KB correct
8 Correct 1 ms 1372 KB correct
9 Correct 1 ms 1372 KB correct
10 Correct 1 ms 1372 KB correct
11 Correct 1 ms 1372 KB correct
12 Correct 1 ms 1372 KB correct
13 Correct 1 ms 1372 KB correct
14 Correct 28 ms 1520 KB correct
15 Correct 28 ms 1620 KB correct
16 Correct 27 ms 1628 KB correct
17 Correct 22 ms 1512 KB correct
18 Correct 9 ms 1476 KB correct
19 Correct 23 ms 1524 KB correct
20 Correct 22 ms 1372 KB correct
21 Correct 21 ms 1372 KB correct
22 Incorrect 11 ms 1504 KB WA in grader: NO
23 Halted 0 ms 0 KB -

Subtask #3
0 / 21.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 1368 KB correct
2 Correct 1 ms 1372 KB correct
3 Correct 1 ms 1372 KB correct
4 Correct 1 ms 1372 KB correct
5 Correct 1 ms 1372 KB correct
6 Correct 1 ms 1372 KB correct
7 Correct 1 ms 1372 KB correct
8 Correct 1 ms 1372 KB correct
9 Correct 1 ms 1372 KB correct
10 Correct 1 ms 1372 KB correct
11 Correct 1 ms 1372 KB correct
12 Correct 1 ms 1372 KB correct
13 Correct 1 ms 1372 KB correct
14 Correct 28 ms 1520 KB correct
15 Correct 28 ms 1620 KB correct
16 Correct 27 ms 1628 KB correct
17 Correct 22 ms 1512 KB correct
18 Correct 9 ms 1476 KB correct
19 Correct 23 ms 1524 KB correct
20 Correct 22 ms 1372 KB correct
21 Correct 21 ms 1372 KB correct
22 Incorrect 11 ms 1504 KB WA in grader: NO
23 Halted 0 ms 0 KB -

Subtask #4
0 / 19.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 1372 KB correct
2 Correct 1 ms 1372 KB correct
3 Incorrect 116 ms 6820 KB WA in grader: NO
4 Halted 0 ms 0 KB -

Subtask #5
0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 1368 KB correct
2 Correct 1 ms 1372 KB correct
3 Correct 1 ms 1372 KB correct
4 Correct 1 ms 1372 KB correct
5 Correct 1 ms 1372 KB correct
6 Correct 1 ms 1372 KB correct
7 Correct 1 ms 1372 KB correct
8 Correct 1 ms 1372 KB correct
9 Correct 1 ms 1372 KB correct
10 Correct 1 ms 1372 KB correct
11 Correct 1 ms 1372 KB correct
12 Correct 1 ms 1372 KB correct
13 Correct 1 ms 1372 KB correct
14 Correct 28 ms 1520 KB correct
15 Correct 28 ms 1620 KB correct
16 Correct 27 ms 1628 KB correct
17 Correct 22 ms 1512 KB correct
18 Correct 9 ms 1476 KB correct
19 Correct 23 ms 1524 KB correct
20 Correct 22 ms 1372 KB correct
21 Correct 21 ms 1372 KB correct
22 Incorrect 11 ms 1504 KB WA in grader: NO
23 Halted 0 ms 0 KB -