Submission #293656

#	Time	Username	Problem	Language	Result	Execution time	Memory
293656		errorgorn	Swapping Cities (APIO20_swap)	C++14	100 / 100	474 ms	56988 KiB

swap

#include "swap.h"

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

#define ll long long
#define ii pair<ll,ll>
#define iii pair<ll,ii>
#define fi first
#define se second

#define rep(x,s,e) for (auto x=s-(s>e);x!=e-(s>e);(s<e?x++:x--))
#define sz(x) (int)(x).size()
#define all(x) (x).begin(),(x).end()

const int INF=1e9+100;

int n,m;
vector<ii> al[100005];
vector<iii> edges,loop;

int p[200005]; //ufds
int find(int i){
	if (i==p[i]) return i;
	else return p[i]=find(p[i]);
}

ll w[200005]; //weight of kruskal tree
ll extra[200005]; //extra stuff (fork, loop)
int pa[200005][20]; //2k decomp on kruskal tree
int d[200005]; //depth for lca query
vector<int> child[200005]; //stupid al

int IDX;

int mov(int i,int k){
	rep(x,0,20) if (k&(1<<x)) {
		i=pa[i][x];
	}
	return i;
}

int lca(int i,int j){
	if (d[i]<d[j]) swap(i,j);
	
	i=mov(i,d[i]-d[j]);
	if (i==j) return i;
	
	rep(x,20,0){
		if (pa[i][x]!=pa[j][x]){
			i=pa[i][x];
			j=pa[j][x];
		}
	}
	
	return pa[i][0];
}

void init(int N, int M,
          std::vector<int> U, std::vector<int> V, std::vector<int> W) {
	
	rep(x,0,200005) p[x]=x;
	memset(pa,-1,sizeof(pa));
	memset(extra,63,sizeof(extra));
	
	n=N,m=M;
	
	rep(x,0,m){
		al[U[x]].push_back(ii(V[x],W[x]));
		al[V[x]].push_back(ii(U[x],W[x]));
		edges.push_back(iii(W[x],ii(V[x],U[x])));
	}
	
	rep(x,0,n){
		vector<int> temp;
		for (auto &it:al[x]) temp.push_back(it.se);
		sort(all(temp));
		
		if (sz(temp)>=3) extra[x]=temp[2];
	}
	
	IDX=n;
	
	sort(all(edges));
	for (auto &it:edges){
		int u=find(it.se.fi),v=find(it.se.se);
		
		if (u==v){
			loop.push_back(it);
			continue;
		}
		w[IDX]=it.fi;
		p[u]=p[v]=IDX;
		child[IDX].push_back(u);
		child[IDX].push_back(v);
		IDX++;
	}
	
	rep(node,IDX,0){
		for (auto &it:child[node]){
			d[it]=d[node]+1;
			int curr=pa[it][0]=node;
			rep(x,0,20){
				if (curr==-1) break;
				curr=pa[it][x+1]=pa[curr][x];
			}
		}
	}
	
	for (auto &it:loop){
		int temp=lca(it.se.se,it.se.se);
		extra[temp]=min(extra[temp],it.fi);
	}
	
	rep(x,0,IDX){
		for (auto &it:child[x]){
			extra[x]=min(extra[x],extra[it]);
		}
		w[x]=max(w[x],extra[x]);
	}
	
	rep(x,IDX,0){
		for (auto &it:child[x]){
			w[it]=min(w[it],w[x]);
		}
	}
}

int getMinimumFuelCapacity(int u, int v) {
	if (w[IDX-1]>=INF) return -1;
	
	u=lca(u,v);
	if (w[u]!=INF) return w[u];
	
	return w[pa[u][0]];
}

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