Submission #495421

#	Time	Username	Problem	Language	Result	Execution time	Memory
495421		pragmatist	Evacuation plan (IZhO18_plan)	C++17	100 / 100	746 ms	84468 KiB

plan

#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][18], mn[N][18], 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 <= 17; ++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(rall(po));
	for(int i = 0; i < m; ++i) {
		int u = po[i].y.x, v = po[i].y.y;
		if(get(u) != get(v)) {
			//cout << u << ' ' << v << ' ' << po[i].x << nl;
			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) << nl;	
	}
}           

signed main() {                   
	ios_base::sync_with_stdio(NULL);
    cin.tie(0);
    cout.tie(0);
   	int test = 1;
	//cin >> test;
	for(int i = 1; i <= test; ++i) {
        //cout << "Case " << i << ": ";
        solve();
    }
    return 0;
}
/*
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: 10 / 10
• Subtask 2: 13 / 13
• Subtask 3: 12 / 12
• Subtask 4: 19 / 19
• Subtask 5: 46 / 46