Submission #200378

#	Time	Username	Problem	Language	Result	Execution time	Memory
200378		arnold518	Designated Cities (JOI19_designated_cities)	C++14	100 / 100	1020 ms	62692 KiB

designated_cities

#include <bits/stdc++.h>
using namespace std;
 
typedef long long ll;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;
 
const int MAXN = 2e5;
 
int N, Q, lf;
map<int, int> adj[MAXN+10];
set<int> leaf[MAXN+10];
 
int pos[MAXN+10];
ll dist[MAXN+10], ans[MAXN+10];
 
void dfs(int now, int bef)
{
	for(auto nxt : adj[now])
	{
		if(nxt.first==bef) continue;
		ans[1]+=nxt.second;
		dfs(nxt.first, now);
	}
}
 
void dfs2(int now, int bef, ll val)
{
	ans[1]=min(ans[1], val);
	for(auto nxt : adj[now])
	{
		if(nxt.first==bef) continue;
		dfs2(nxt.first, now, val-adj[now][nxt.first]+adj[nxt.first][now]);
	}
}
 
pll propa(int u)
{
	int now=u, nxt; ll ret=0;
	while(adj[now].size()==1 && leaf[now].size()==0)
	{
		nxt=adj[now].begin()->first;
		ret+=adj[nxt][now];
		adj[now].erase(nxt); adj[nxt].erase(now);
		now=nxt;
	}
	return {now, ret};
}
 
int main()
{
	int i, j;
 
	scanf("%d", &N);
	for(i=1; i<N; i++)
	{
		int a, b, c, d;
		scanf("%d%d%d%d", &a, &b, &c, &d);
		adj[a][b]=c;
		adj[b][a]=d;
	}
 
	dfs2(1, 1, 0);
	dfs(1, 1);
 
	set<pll> PQ;
	vector<int> V;
	for(i=1; i<=N; i++) if(adj[i].size()==1) V.push_back(i);
	for(auto i : V)
	{
		pll t=propa(i);
		leaf[t.first].insert(i);
		dist[i]=t.second;
		pos[i]=t.first;
		PQ.insert({dist[i], i});
		//printf("%d %lld\n", i, dist[i]);
		lf++;
	}
 
	ll cost=0;
	for(i=lf-1; i>=2; i--)
	{
		pll now=*PQ.begin(); PQ.erase(PQ.begin());
		cost+=now.first;
		//printf("!%lld %lld\n", now.first, now.second);
		assert(adj[now.second].size()==0);
		leaf[pos[now.second]].erase(now.second);
		if(leaf[pos[now.second]].size()==1)
		{
			int u=*leaf[pos[now.second]].begin();
			leaf[pos[now.second]].erase(leaf[pos[now.second]].begin());
			PQ.erase({dist[u], u});
			pll t=propa(pos[now.second]);
			leaf[t.first].insert(u);
			dist[u]+=t.second;
			pos[u]=t.first;
			PQ.insert({dist[u], u});
		}
		ans[i]=cost;
	}
 
	scanf("%d", &Q);
	while(Q--)
	{
		int p;
		scanf("%d", &p);
		printf("%lld\n", ans[p]);
	}
}

Compilation message (stderr)

designated_cities.cpp: In function 'int main()':
designated_cities.cpp:52:9: warning: unused variable 'j' [-Wunused-variable]
  int i, j;
         ^
designated_cities.cpp:54:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d", &N);
  ~~~~~^~~~~~~~~~
designated_cities.cpp:58:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   scanf("%d%d%d%d", &a, &b, &c, &d);
   ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~
designated_cities.cpp:102:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d", &Q);
  ~~~~~^~~~~~~~~~
designated_cities.cpp:106:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   scanf("%d", &p);
   ~~~~~^~~~~~~~~~

• Subtask 1: 6 / 6
• Subtask 2: 7 / 7
• Subtask 3: 9 / 9
• Subtask 4: 17 / 17
• Subtask 5: 17 / 17
• Subtask 6: 44 / 44