Submission #945296

#	Time	Username	Problem	Language	Result	Execution time	Memory
945296		oblantis	Evacuation plan (IZhO18_plan)	C++17	100 / 100	391 ms	45728 KiB

plan

//#pragma GCC target("avx2,bmi,bmi2,lzcnt,popcnt")
//#pragma GCC optimize("O3,unroll-loops")
#include <bits/stdc++.h>
#define all(v) v.begin(), v.end()
#define pb push_back
#define ss second
#define ff first
#define vt vector
using namespace std;
typedef long long ll;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;
const ll inf = 1e15;
const int mod = 1e9+7;
const int maxn = 1e5 + 1;
vt<pii> g[maxn];
vt<int> adj[maxn];
ll dp[maxn];
int p[maxn], deep[maxn], up[maxn][20];
bool was[maxn];
bool cmp(int x, int y){
	return dp[x] < dp[y];
}
int get(int wt){
	if(p[wt] == wt)return wt;
	p[wt] = get(p[wt]);
	return p[wt];
}
void go(int v){
	for(auto i : adj[v]){
		deep[i] = deep[v] + 1;
		up[i][0] = v;
		go(i);
	}
}
int calc(int x, int y){
	if(deep[x] > deep[y])swap(x, y);
	int fup = deep[y] - deep[x], j = 0;
	while(fup){
		if(fup & 1){
			y = up[y][j];
		}
		j++;
		fup >>= 1;
	}
	if(y == x)return y;
	for(int i = 19; i >= 0; i--){
		if(up[y][i] != up[x][i])x = up[x][i], y = up[y][i];
	}
	return up[x][0];
}
void solve() {
	int n, m;
	cin >> n >> m;
	fill(dp, dp + n + 1, inf);
	vt<int> it(n);
	for(int i = 1; i <= n; i++){
		it.pb(i);
		p[i] = i;
	}
	for(int i = 0, u, v, w; i < m; i++){
		cin >> u >> v >> w;
		g[u].pb({v, w});
		g[v].pb({u, w});
	}
	int k;
	priority_queue<pair<ll, int>, vt<pair<ll, int>>, greater<pair<ll, int>>> pq;
	cin >> k;
	for(int i = 0; i < k; i++){
		int wt;
		cin >> wt;
		dp[wt] = 0;
		pq.push({0, wt});
	}
	while(!pq.empty()){
		pair<ll, int> nw = pq.top();
		pq.pop();
		if(nw.ff != dp[nw.ss])continue;
		for(auto i : g[nw.ss]){
			if(dp[i.ff] > nw.ff + i.ss){
				dp[i.ff] = nw.ff + i.ss;
				pq.push({dp[i.ff], i.ff});
			}
		}
	}
	sort(all(it), cmp);
	for(int i = n - 1; i >= 0; i--){
		was[it[i]] = 1;
		for(auto j : g[it[i]]){
			if(!was[j.ff])continue;
			get(j.ff);
			if(p[j.ff] == it[i])continue;
			adj[it[i]].pb(p[j.ff]);
			p[p[j.ff]] = it[i];
		}
	}
	go(it[0]);
	for(int i = 1; i < 20; i++)for(int j = 1; j <= n; j++)up[j][i] = up[up[j][i - 1]][i - 1];
	int q;
	cin >> q;
	while(q--){
		int s, t;
		cin >> s >> t;
		cout << dp[calc(s, t)] << '\n';
	}
}
int main() {
	ios_base::sync_with_stdio(0);
	cin.tie(0);
	int times = 1;
	//cin >> times;
	for(int i = 1; i <= times; i++) {
		solve();
	}
	return 0;
}

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