Submission #500909

#	Time	Username	Problem	Language	Result	Execution time	Memory
500909		dostigator	Evacuation plan (IZhO18_plan)	C++17	0 / 100	269 ms	45252 KiB

plan

// author lox:( not mine

#include <bits/stdc++.h>

#define pb push_back
#define sz(v) (int)v.size()
#define all(v) v.begin(),v.end()
#define rall(v) v.rbegin(),v.rend()
#define x first
#define y second
#define nl "\n"

using namespace std;

typedef long long ll;
typedef pair<long long, long long> pll;
typedef pair <ll, ll> pii;

const int N = (int)1e5 + 7;
const int M = (int)7e6 + 7;
const ll MOD = (ll)1e9 + 7;
const int inf = (int)1e9 + 7;
const ll INF = (ll)3e18 + 7;

pii dir[] = {{-1, -1}, {1, 1}, {-1, 1}, {1, -1}};
int n,m,k,s,t,ans,Q,d[N],e[N];
int p[N],sz[N];
int timer,tin[N],tout[N],up[N][19],mn[N][19],di[N];
vector<pii>g[N],gr[N];
bool used[N];
int get(int v) {
	if(p[v]==v) return v;
	return p[v]=get(p[v]);
}
void comb(int u,int v) {
	u=get(u);
	v=get(v);
	if(sz[u]>sz[v]) swap(u,v);
	p[u]=v;
	sz[v]+=sz[u];
}
void calc(int v,int pr,int cst) {
    tin[v]=++timer;
	up[v][0]=pr;
	mn[v][0]=cst;
	for(int i=1; i<=18; ++i) {
		up[v][i]=up[up[v][i-1]][i-1];
		mn[v][i]=min(mn[v][i-1],mn[up[v][i-1]][i-1]);
	}
	for(auto [to, w]:gr[v]) {
		if(to!=pr){
			di[to]=di[v]+1;
			calc(to,v,w);
		}
	}
	tout[v]=++timer;
}
bool is_parent(int u,int v) {return tin[u]<=tin[v] && tout[u]>=tout[v];}
int lca(int u,int v) {
	if(is_parent(u,v)) return u;
	if(is_parent(v,u)) return v;
	for(int i=17; i>=0; --i) if(!is_parent(up[u][i],v)) u=up[u][i];
	return up[u][0];
}
int get(int u,int v) {
	int k=lca(u,v),x=di[u]-di[k],y=di[v]-di[k];
	int res=inf;
	for(int i=17; i>=0; --i) {
		if(x>>i&1) res=min(res,mn[u][i]),u=up[u][i];
		if(y>>i&1) res=min(res,mn[v][i]),v=up[v][i];
	}
	return res;
}
void solve(){
    cin>>n>>m;
	vector<pii>edge;
	for(int i=1; i<=n; ++i) sz[i]=1,p[i]=i;
	for(int i=1; i<=m; ++i){
		int u,v,w;
		cin>>u>>v>>w;
		edge.pb({u,v});
		g[u].pb({v,w});
		g[v].pb({u,w});
	}
	cin>>k;
	for(int i=1; i<=n; ++i) d[i]=inf;
	set<pii>q;
	for(int i=1; i<=k; ++i) {
		int x;
		cin>>x;
		d[x]=0;
		q.insert({0,x});
	}
	while(!q.empty()) {
		int v=(*q.begin()).y;
		q.erase(q.begin());
		for(auto [to,w]:g[v]) {
			if(d[v]+w<d[to]) {
				q.erase({d[to],to});
				d[to]=d[v]+w;
				q.insert({d[to],to});
			}
		}
	}
	vector<pair<int,pii>>po;
	for(auto [u,v]:edge)po.pb({min(d[u],d[v]),{u,v}});
	sort(all(po));
	for(int i=0; i<m; ++i) {
		int u=po[i].y.x,v=po[i].y.y;
		if(get(u)!=get(v)) {
			gr[u].pb({v,po[i].x});
			gr[v].pb({u,po[i].x});
			comb(u,v);
		}
	}
	calc(1,1,inf);
	cin>>Q;
	while(Q--) {
		cin>>s>>t;
		cout<<get(s,t)<<endl;
	}
}
int main() {
    //fre_open();
    ios_base::sync_with_stdio(NULL);
    cin.tie(0);
    cout.tie(0);
    ll tt=1;
    //cin>>tt;
    while(tt--) solve();
}
/*
9 12
1 9 4
1 2 5
2 3 7
2 4 3
4 3 6
3 6 4
8 7 10
6 7 5
5 8 1
9 5 7
5 4 12
6 8 2
2
4 7
5
1 6
5 3
4 8
5 8
1 5*/

• Subtask 1: 0 / 10
• Subtask 2: 0 / 13
• Subtask 3: 0 / 12
• Subtask 4: 0 / 19
• Subtask 5: 0 / 46