Submission #521601

#	Time	Username	Problem	Language	Result	Execution time	Memory
521601		eecs	Keys (IOI21_keys)	C++17	100 / 100	1608 ms	53216 KiB

keys

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

vector<int> find_reachable(vector<int> r, vector<int> U, vector<int> V, vector<int> C) {
	int n = r.size(), mn = INT_MAX;
	vector<vector<array<int, 2>>> G(n);
	for (int i = 0; i < U.size(); i++) {
		G[U[i]].push_back({V[i], C[i]});
		G[V[i]].push_back({U[i], C[i]});
	}
	vector<int> ans, perm(n), pos(n), vis(n, -1), visc(n, -1);
	vector<vector<int>> cand(n);
	iota(perm.begin(), perm.end(), 0);
	vector<int> cnt(n);
	for (int i = 0; i < n; i++) {
		for (auto &e : G[i]) if (e[1] == r[i]) cnt[i]++;
	}
	sort(perm.begin(), perm.end(), [&](int u, int v) { return cnt[u] < cnt[v]; });
	for (int i = 0; i < n; i++) {
		pos[perm[i]] = i;
	}
	for (int i = 0; i < n; i++) {
		sort(G[i].begin(), G[i].end(), [&](array<int, 2> p, array<int, 2> q) { return pos[p[0]] < pos[q[0]]; });
	}
	queue<int> Q;
	vector<bool> solved(n);
	vector<int> ver, col;
	for (int x : perm) {
		ver = {x}, col.clear();
		while (!Q.empty()) Q.pop();
		Q.push(x), vis[x] = x, solved[x] = 1;
		while (!Q.empty()) {
			int u = Q.front(); Q.pop();
			if (visc[r[u]] ^ x) {
				for (int v : cand[r[u]]) if (vis[v] ^ x) {
					ver.push_back(v), Q.push(v), vis[v] = x;
					if (solved[v] || ver.size() > mn) goto nxt;
				}
				visc[r[u]] = x;
			}
			for (auto &e : G[u]) if (vis[e[0]] ^ x) {
				if (visc[e[1]] == x) {
					ver.push_back(e[0]), Q.push(e[0]), vis[e[0]] = x;
					if (solved[e[0]] || ver.size() > mn) goto nxt;
				} else {
					col.push_back(e[1]);
					if (solved[e[0]]) cand[e[1]].clear();
					cand[e[1]].push_back(e[0]);
				}
			}
		}
		if (ver.size() < mn) mn = ver.size(), ans = ver;
		else copy(ver.begin(), ver.end(), back_inserter(ans));
	nxt:;
		for (int c : col) cand[c].clear();
	}
	vector<int> res(n);
	for (int x : ans) res[x] = 1;
	return res;
}

Compilation message (stderr)

keys.cpp: In function 'std::vector<int> find_reachable(std::vector<int>, std::vector<int>, std::vector<int>, std::vector<int>)':
keys.cpp:8:20: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
    8 |  for (int i = 0; i < U.size(); i++) {
      |                  ~~^~~~~~~~~~
keys.cpp:38:34: warning: comparison of integer expressions of different signedness: 'std::vector<int>::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
   38 |      if (solved[v] || ver.size() > mn) goto nxt;
      |                       ~~~~~~~~~~~^~~~
keys.cpp:45:37: warning: comparison of integer expressions of different signedness: 'std::vector<int>::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
   45 |      if (solved[e[0]] || ver.size() > mn) goto nxt;
      |                          ~~~~~~~~~~~^~~~
keys.cpp:53:18: warning: comparison of integer expressions of different signedness: 'std::vector<int>::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
   53 |   if (ver.size() < mn) mn = ver.size(), ans = ver;
      |       ~~~~~~~~~~~^~~~

• Subtask 1: 9 / 9
• Subtask 2: 11 / 11
• Subtask 3: 17 / 17
• Subtask 4: 30 / 30
• Subtask 5: 33 / 33