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Submission #1080553

# Submission time Handle Problem Language Result Execution time Memory
1080553 2024-08-29T10:54:09 Z Joshua_Andersson Simurgh (IOI17_simurgh) C++14
30 / 100
 164 ms 8392 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], known[maxm];

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
		{
			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;
				known[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];
			}

			
			bool q_known = 0;
			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);
				}
				if (known[cycle[i]])
				{
					int k = count_common_roads(q);
					if (!is_golden[cycle[i]])
					{
						mx = k;
					}
					else mx = k + 1;
				}
				else
				{
					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;
				}
				known[v.first] = 1;
			}
		}
	}
	
	assert(sz(spanning) == n - 1);

	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;
}

Compilation message

simurgh.cpp: In function 'std::vector<int> find_roads(int, std::vector<int>, std::vector<int>)':
simurgh.cpp:138:9: warning: unused variable 'q_known' [-Wunused-variable]
  138 |    bool q_known = 0;
      |         ^~~~~~~

Subtask #1
13.0 / 13.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 3164 KB correct
2 Correct 1 ms 3164 KB correct
3 Correct 1 ms 3164 KB correct
4 Correct 1 ms 3164 KB correct
5 Correct 1 ms 3164 KB correct
6 Correct 1 ms 3164 KB correct
7 Correct 1 ms 3160 KB correct
8 Correct 1 ms 3164 KB correct
9 Correct 1 ms 3164 KB correct
10 Correct 1 ms 3164 KB correct
11 Correct 1 ms 3164 KB correct
12 Correct 1 ms 3164 KB correct
13 Correct 1 ms 3164 KB correct

Subtask #2
17.0 / 17.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 3164 KB correct
2 Correct 1 ms 3164 KB correct
3 Correct 1 ms 3164 KB correct
4 Correct 1 ms 3164 KB correct
5 Correct 1 ms 3164 KB correct
6 Correct 1 ms 3164 KB correct
7 Correct 1 ms 3160 KB correct
8 Correct 1 ms 3164 KB correct
9 Correct 1 ms 3164 KB correct
10 Correct 1 ms 3164 KB correct
11 Correct 1 ms 3164 KB correct
12 Correct 1 ms 3164 KB correct
13 Correct 1 ms 3164 KB correct
14 Correct 32 ms 3420 KB correct
15 Correct 32 ms 3412 KB correct
16 Correct 28 ms 3416 KB correct
17 Correct 22 ms 3164 KB correct
18 Correct 9 ms 3164 KB correct
19 Correct 23 ms 3328 KB correct
20 Correct 22 ms 3420 KB correct
21 Correct 25 ms 3164 KB correct
22 Correct 11 ms 3160 KB correct
23 Correct 9 ms 3164 KB correct
24 Correct 8 ms 3164 KB correct
25 Correct 1 ms 3164 KB correct
26 Correct 8 ms 3164 KB correct
27 Correct 9 ms 3164 KB correct
28 Correct 3 ms 3164 KB correct
29 Correct 2 ms 3164 KB correct
30 Correct 15 ms 3160 KB correct
31 Correct 15 ms 3164 KB correct
32 Correct 14 ms 3300 KB correct
33 Correct 14 ms 3164 KB correct

Subtask #3
0 / 21.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 3164 KB correct
2 Correct 1 ms 3164 KB correct
3 Correct 1 ms 3164 KB correct
4 Correct 1 ms 3164 KB correct
5 Correct 1 ms 3164 KB correct
6 Correct 1 ms 3164 KB correct
7 Correct 1 ms 3160 KB correct
8 Correct 1 ms 3164 KB correct
9 Correct 1 ms 3164 KB correct
10 Correct 1 ms 3164 KB correct
11 Correct 1 ms 3164 KB correct
12 Correct 1 ms 3164 KB correct
13 Correct 1 ms 3164 KB correct
14 Correct 32 ms 3420 KB correct
15 Correct 32 ms 3412 KB correct
16 Correct 28 ms 3416 KB correct
17 Correct 22 ms 3164 KB correct
18 Correct 9 ms 3164 KB correct
19 Correct 23 ms 3328 KB correct
20 Correct 22 ms 3420 KB correct
21 Correct 25 ms 3164 KB correct
22 Correct 11 ms 3160 KB correct
23 Correct 9 ms 3164 KB correct
24 Correct 8 ms 3164 KB correct
25 Correct 1 ms 3164 KB correct
26 Correct 8 ms 3164 KB correct
27 Correct 9 ms 3164 KB correct
28 Correct 3 ms 3164 KB correct
29 Correct 2 ms 3164 KB correct
30 Correct 15 ms 3160 KB correct
31 Correct 15 ms 3164 KB correct
32 Correct 14 ms 3300 KB correct
33 Correct 14 ms 3164 KB correct
34 Incorrect 164 ms 4952 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 3160 KB correct
2 Correct 1 ms 3164 KB correct
3 Incorrect 114 ms 8392 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 3164 KB correct
2 Correct 1 ms 3164 KB correct
3 Correct 1 ms 3164 KB correct
4 Correct 1 ms 3164 KB correct
5 Correct 1 ms 3164 KB correct
6 Correct 1 ms 3164 KB correct
7 Correct 1 ms 3160 KB correct
8 Correct 1 ms 3164 KB correct
9 Correct 1 ms 3164 KB correct
10 Correct 1 ms 3164 KB correct
11 Correct 1 ms 3164 KB correct
12 Correct 1 ms 3164 KB correct
13 Correct 1 ms 3164 KB correct
14 Correct 32 ms 3420 KB correct
15 Correct 32 ms 3412 KB correct
16 Correct 28 ms 3416 KB correct
17 Correct 22 ms 3164 KB correct
18 Correct 9 ms 3164 KB correct
19 Correct 23 ms 3328 KB correct
20 Correct 22 ms 3420 KB correct
21 Correct 25 ms 3164 KB correct
22 Correct 11 ms 3160 KB correct
23 Correct 9 ms 3164 KB correct
24 Correct 8 ms 3164 KB correct
25 Correct 1 ms 3164 KB correct
26 Correct 8 ms 3164 KB correct
27 Correct 9 ms 3164 KB correct
28 Correct 3 ms 3164 KB correct
29 Correct 2 ms 3164 KB correct
30 Correct 15 ms 3160 KB correct
31 Correct 15 ms 3164 KB correct
32 Correct 14 ms 3300 KB correct
33 Correct 14 ms 3164 KB correct
34 Incorrect 164 ms 4952 KB WA in grader: NO
35 Halted 0 ms 0 KB -