Submission #850657

#	Time	Username	Problem	Language	Result	Execution time	Memory
850657		Hyojin	Swapping Cities (APIO20_swap)	C++17	100 / 100	249 ms	62852 KiB

swap

#include <bits/stdc++.h>
using namespace std;
#define bit(n,i) ((n>>i)&1) 
#define all(a) (a).begin(),(a).end()
#define pb push_back
#define ep emplace_back
#define pii pair<int,int>
#define piii pair<int,pii> 
#define fi first
#define se second
#define ll long long
#define debug(x) cerr << #x << ' ' << x << '\n'
#define dbg(x) cerr<<#x<<' '<<x<<' '
const int base=31;
const int MOD=1e9+7;
const int N=3e5+5;
int ans[N],value[N],lab[N],deg[N],p[N][20],depth[N],n,m;
bool ok[N];
vector<int>adj[N];
int find_set(int v)
{
	return (lab[v]==v?v:lab[v]=find_set(lab[v]));
}
void join(int u,int v,int w)
{
	lab[n]=n;
	value[n]=w;
	deg[u]++;
	deg[v]++;
	if (deg[u]>=3||deg[v]>=3) ok[n]=1;
	u=find_set(u);
	v=find_set(v);
	adj[n].pb(u);
	lab[u]=n;
	if (u!=v)
	{
		adj[n].pb(v);
		lab[v]=n;
	}
	ok[n]|=ok[u]|ok[v];
	++n;
}
int lca(int u,int v)
{
	if (depth[u]<depth[v]) swap(u,v);
	for (int i=18;~i;i--)
	{
		if (depth[u]-(1<<i)>=depth[v]) u=p[u][i];
	}
	if (u==v) return u;
	for (int i=18;~i;i--)
	{
		if (~p[u][i]&&p[u][i]!=p[v][i])
		{
			u=p[u][i];
			v=p[v][i];
		}
	}
	return p[u][0];
}
void dfs(int u,int par)
{
	if (ok[u]||adj[u].size()==1) ans[u]=value[u];
	else if (u!=par) ans[u]=ans[par];
	else ans[u]=-1;
	for (int v:adj[u])
	{
		if (v==par) continue;
		depth[v]=depth[u]+1;
		p[v][0]=u;
		dfs(v,u);
	}
}
void init(int N,int M,vector<int>U,vector<int>V,vector<int>W)
{
	memset(p,-1,sizeof p);
	n=N,m=M;
	for (int i=0;i<n;i++) lab[i]=i;
	vector<int>id;
	for (int i=0;i<m;i++) id.pb(i);
	sort(all(id),[&](int x,int y){return W[x]<W[y];});
	for (auto idx:id)
	{
		join(U[idx],V[idx],W[idx]);
	}
	dfs(n-1,n-1);
	for (int j=1;(1<<j)<n;j++)
	{
		for (int i=0;i<n;i++)
		{
			if (~p[i][j-1])
			{
				p[i][j]=p[p[i][j-1]][j-1];
			}
		}
	}
}
int getMinimumFuelCapacity(int X,int Y)
{
	return ans[lca(X,Y)];
}

• Subtask 1: 6 / 6
• Subtask 2: 7 / 7
• Subtask 3: 17 / 17
• Subtask 4: 20 / 20
• Subtask 5: 23 / 23
• Subtask 6: 27 / 27