Submission #545157

#	Time	Username	Problem	Language	Result	Execution time	Memory
545157		MilosMilutinovic	Swapping Cities (APIO20_swap)	C++14	7 / 100	349 ms	39508 KiB

swap

#include "swap.h"
#include <bits/stdc++.h>

#define fi first
#define se second
#define pb push_back
#define mp make_pair

using namespace std;

typedef long long ll;
typedef unsigned long long ull;
typedef pair<int,int> pii;
typedef pair<ll,ll> pll;

template<typename T> bool chkmin(T&x,T y){return x>y?x=y,1:0;}
template<typename T> bool chkmax(T&x,T y){return x<y?x=y,1:0;}

int n,m,fa[300005],f[300005][20],val[300005],dep[300005],tl[300005],tr[300005],ok[300005],up[300005];
array<int,3> edg[200005];
vector<int> adj[300005];

int getf(int x){return x==fa[x]?x:fa[x]=getf(fa[x]);}

void dfs(int u,int p){
	up[u]=(ok[u]?u:up[p]);
	dep[u]=dep[p]+1;
	f[u][0]=p;
	for(int i=1;i<20;i++) f[u][i]=f[f[u][i-1]][i-1];
	for(int v:adj[u]) dfs(v,u);
}

int lca(int x,int y){
	if(dep[x]<dep[y]) swap(x,y);
	for(int i=19;i>=0;i--) if(dep[f[x][i]]>=dep[y]) x=f[x][i];
	if(x==y) return x;
	for(int i=19;i>=0;i--) if(f[x][i]!=f[y][i]) x=f[x][i],y=f[x][i];
	return f[x][0];
}

void init(int N,int M,vector<int> U,vector<int> V,vector<int> W){
	n=N; m=M;
	for(int i=0;i<m;i++) edg[i+1]={W[i],U[i]+1,V[i]+1};
	sort(edg+1,edg+m+1);
	for(int i=1;i<=n;i++) tl[i]=tr[i]=i;
	for(int i=1;i<=n+m;i++) fa[i]=i;
	for(int i=1;i<=m;i++){
		int u=edg[i][1],v=edg[i][2],w=edg[i][0];
		val[n+i]=w;
		u=getf(u); v=getf(v); fa[u]=fa[v]=n+i;
		ok[n+i]=(ok[u]|ok[v]|(u==v?1:0));
		bool found=false;
		for(int x:{tl[u],tr[u]}){
			for(int y:{tl[v],tr[v]}){
				if((x==edg[i][1]&&y==edg[i][2])||(x==edg[i][2]&&y==edg[i][1])){
					found=true; tl[n+i]=(x^tl[u]^tr[u]); tr[n+i]=(y^tl[v]^tr[v]);
				}
			}
		}
		if(!found) ok[n+i]=1;
		adj[n+i].pb(u); if(u!=v) adj[n+i].pb(v);
	}
	dfs(n+m,0);
}

int getMinimumFuelCapacity(int X,int Y){
	if(!ok[n+m]) return -1;
	X++; Y++;
	assert(lca(X,Y)>=1&&lca(X,Y)<=n+m);
	return val[up[lca(X,Y)]];
}

/*
5 6
0 1 4
0 2 4
1 2 1
1 3 2
1 4 10
2 3 3
3
1 2
2 4
0 1

3 2
0 1 5
0 2 5
1
1 2
*/

• Subtask 1: 0 / 6
• Subtask 2: 7 / 7
• Subtask 3: 0 / 17
• Subtask 4: 0 / 20
• Subtask 5: 0 / 23
• Subtask 6: 0 / 27