Submission #574574

#	Time	Username	Problem	Language	Result	Execution time	Memory
574574		FatihSolak	Min-max tree (BOI18_minmaxtree)	C++17	100 / 100	850 ms	75076 KiB

minmaxtree

#include <bits/stdc++.h>
#define N 200005
#define K 20
using namespace std;
vector<int> adj[N];
map<pair<int,int>,pair<int,int>> edge;
set<int> s[N][2];
map<int,bool> needed;
void dfs1(int v,int pr){
	for(auto u:adj[v]){
		if(u == pr)continue;
		dfs1(u,v);
		for(int i = 0;i<2;i++){
			if(s[u][i].size() > s[v][i].size()){
				swap(s[u][i],s[v][i]);
			}
			for(auto c:s[u][i]){
				if(s[v][i].count(c))s[v][i].erase(c);
				else s[v][i].insert(c);
			}
		}
	}
	if(s[v][0].size()){
		edge[{min(v,pr),max(v,pr)}].first = max(edge[{min(v,pr),max(v,pr)}].first,*s[v][0].rbegin());
	}
	if(s[v][1].size()){
		edge[{min(v,pr),max(v,pr)}].second = min(edge[{min(v,pr),max(v,pr)}].second,*s[v][1].begin());
	}
}
void solve(){
	int n;
	cin >> n;
	map<pair<int,int>,int> ans;
	for(int i = 1;i<n;i++){
		int u,v;
		cin >> u >> v;
		adj[u].push_back(v);
		adj[v].push_back(u);
		edge[{min(u,v),max(u,v)}] = {-2e9,2e9};
		ans[{min(u,v),max(u,v)}] = 2e9;
	}
	int k;
	cin >> k;
	for(int i = 1;i<=k;i++){
		char type;
		int u,v,x;
		cin >> type >> u >> v >> x;
		needed[x] = 1;
		if(type == 'M'){
			s[u][1].insert(x);
			s[v][1].insert(x);
		}
		if(type == 'm'){
			s[u][0].insert(x);
			s[v][0].insert(x);
		}
	}
	dfs1(1,0);
	map<int,set<pair<int,pair<int,int>>>> adj2;
	for(auto u:edge){
		if(needed[u.second.first]){
			adj2[u.second.first].insert({u.second.second,u.first});
		}
		if(needed[u.second.second]){
			adj2[u.second.second].insert({u.second.first,u.first});
		}
	}
	set<pair<int,int>> ss;
	for(auto u:adj2){
		ss.insert({u.second.size(),u.first});
	}
	while(ss.size()){
		int num = ss.begin()->second;
		ss.erase(ss.begin());
		needed[num] = 0;
		ans[adj2[num].begin()->second] = num;
		if(needed[adj2[num].begin()->first]){
			ss.erase({adj2[adj2[num].begin()->first].size(),adj2[num].begin()->first});
			adj2[adj2[num].begin()->first].erase({num,adj2[num].begin()->second});
			ss.insert({adj2[adj2[num].begin()->first].size(),adj2[num].begin()->first});
		}

	}
	assert(ans.size() == n-1);
	for(auto u:needed){
		assert(u.second == 0); 
	}
	for(auto u:ans){
		if(u.second == 2e9){
			u.second = edge[u.first].first;
		}
		cout << u.first.first << " " << u.first.second << " "<< u.second << endl;
	}
}
int main(){
	ios_base::sync_with_stdio(false);
	cin.tie(nullptr);
	#ifdef Local
		freopen("in.txt","r",stdin);
		freopen("out.txt","w",stdout);
	#endif
	int t = 1;
	//cin >> t;
	while(t--){
		solve();
	}
	#ifdef Local
		cout << endl << fixed << setprecision(2) << 1000.0 * clock() / CLOCKS_PER_SEC << " milliseconds.";
	#endif
}

Compilation message (stderr)

In file included from /usr/include/c++/10/cassert:44,
                 from /usr/include/x86_64-linux-gnu/c++/10/bits/stdc++.h:33,
                 from minmaxtree.cpp:1:
minmaxtree.cpp: In function 'void solve()':
minmaxtree.cpp:84:20: warning: comparison of integer expressions of different signedness: 'std::map<std::pair<int, int>, int>::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
   84 |  assert(ans.size() == n-1);
      |         ~~~~~~~~~~~^~~~~~

• Subtask 1: 7 / 7
• Subtask 2: 22 / 22
• Subtask 3: 29 / 29
• Subtask 4: 42 / 42