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Submission #1080515

# Submission time Handle Problem Language Result Execution time Memory
1080515 2024-08-29T10:38:44 Z Joshua_Andersson Simurgh (IOI17_simurgh) C++14
30 / 100
 161 ms 6828 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)
{
	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]);
			depth[e.first] = depth[u] + 1;
			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);
			if (maxup[e.first]>=depth[e.first]) // bridge
			{
				is_golden[e.second] = 1;
			}
			maxup[u] = min(maxup[u], maxup[e.first]);
		}
	}
}

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 1224 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
17.0 / 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 1224 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 1524 KB correct
15 Correct 28 ms 1620 KB correct
16 Correct 28 ms 1628 KB correct
17 Correct 22 ms 1368 KB correct
18 Correct 9 ms 1368 KB correct
19 Correct 23 ms 1372 KB correct
20 Correct 24 ms 1628 KB correct
21 Correct 21 ms 1372 KB correct
22 Correct 11 ms 1372 KB correct
23 Correct 9 ms 1372 KB correct
24 Correct 8 ms 1488 KB correct
25 Correct 1 ms 1372 KB correct
26 Correct 8 ms 1372 KB correct
27 Correct 9 ms 1492 KB correct
28 Correct 3 ms 1372 KB correct
29 Correct 2 ms 1372 KB correct
30 Correct 15 ms 1488 KB correct
31 Correct 14 ms 1368 KB correct
32 Correct 14 ms 1372 KB correct
33 Correct 14 ms 1368 KB correct

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 1224 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 1524 KB correct
15 Correct 28 ms 1620 KB correct
16 Correct 28 ms 1628 KB correct
17 Correct 22 ms 1368 KB correct
18 Correct 9 ms 1368 KB correct
19 Correct 23 ms 1372 KB correct
20 Correct 24 ms 1628 KB correct
21 Correct 21 ms 1372 KB correct
22 Correct 11 ms 1372 KB correct
23 Correct 9 ms 1372 KB correct
24 Correct 8 ms 1488 KB correct
25 Correct 1 ms 1372 KB correct
26 Correct 8 ms 1372 KB correct
27 Correct 9 ms 1492 KB correct
28 Correct 3 ms 1372 KB correct
29 Correct 2 ms 1372 KB correct
30 Correct 15 ms 1488 KB correct
31 Correct 14 ms 1368 KB correct
32 Correct 14 ms 1372 KB correct
33 Correct 14 ms 1368 KB correct
34 Incorrect 161 ms 3248 KB WA in grader: NO
35 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 117 ms 6828 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 1224 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 1524 KB correct
15 Correct 28 ms 1620 KB correct
16 Correct 28 ms 1628 KB correct
17 Correct 22 ms 1368 KB correct
18 Correct 9 ms 1368 KB correct
19 Correct 23 ms 1372 KB correct
20 Correct 24 ms 1628 KB correct
21 Correct 21 ms 1372 KB correct
22 Correct 11 ms 1372 KB correct
23 Correct 9 ms 1372 KB correct
24 Correct 8 ms 1488 KB correct
25 Correct 1 ms 1372 KB correct
26 Correct 8 ms 1372 KB correct
27 Correct 9 ms 1492 KB correct
28 Correct 3 ms 1372 KB correct
29 Correct 2 ms 1372 KB correct
30 Correct 15 ms 1488 KB correct
31 Correct 14 ms 1368 KB correct
32 Correct 14 ms 1372 KB correct
33 Correct 14 ms 1368 KB correct
34 Incorrect 161 ms 3248 KB WA in grader: NO
35 Halted 0 ms 0 KB -