Submission #995687

#	Time	Username	Problem	Language	Result	Execution time	Memory
995687		Acanikolic	Evacuation plan (IZhO18_plan)	C++14	100 / 100	313 ms	61140 KiB

plan

#include <bits/stdc++.h>  

#define pb push_back
 
#define F first
 
#define S second
 
using namespace std;
 
const int N = 1e5 + 10;
 
const int mod = 998244353;
 
const int inf = 1e9;
 
const int LOG = 17; 
 
vector<pair<int,int>>g[N],graf[N]; 
bool mark[N]; 
long long dist[N];
int par[N],siz[N],up[N][LOG],mn[N][LOG],val[N],in[N],out[N],timer = 0,dep[N];

int get(int x) {
	return (x == par[x] ? x : par[x] = get(par[x]));
}

void unite(int u,int v) {
	u = get(u);
	v = get(v);
	if(u == v) return;
	if(siz[u] > siz[v]) swap(u,v);
	siz[v] += siz[u];
	par[u] = v;
}

bool same(int u,int v) {
	return get(u) == get(v);
}

bool cmp(array<int,3>A,array<int,3>B) {
	return A[2] > B[2];
}

void dfs(int x,int par) {
	dep[x] = dep[par] + 1;
	in[x] = ++timer;
	up[x][0] = par;
	mn[x][0] = val[x];
	for(int j = 1; j < LOG; j++) {
		up[x][j] = up[up[x][j - 1]][j - 1];
		mn[x][j] = min(mn[x][j - 1],mn[up[x][j - 1]][j - 1]);
	}
	for(auto X : graf[x]) {
		if(X.F == par) continue;
		val[X.F] = X.S;
		dfs(X.F,x);
	}
	out[x] = timer;
}

bool intree(int u,int v) {
	return in[u] <= in[v] && out[u] >= out[v];
}

int lca(int u,int v) {
	if(intree(u,v)) return u;
	if(intree(v,u)) return v;
	for(int j = LOG - 1; j >= 0; j--) {
		if(up[u][j] > 0 && !intree(up[u][j],v)) u = up[u][j];
	}
	return up[u][0];
}

int get(int u,int LCA) {
	int k = dep[u] - dep[LCA],res = inf;
	for(int j = LOG - 1; j >= 0; j--) {
		if((1 << j) & k) {
			res = min(res,mn[u][j]);
			u = up[u][j];
		}
	}
	return res;
}
 
signed main() {
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
 
 	int n,m;
 	cin >> n >> m;
 	for(int i = 1; i <= n; i++) {
 		dist[i] = inf;
 		par[i] = i;
 		siz[i] = 1;
 	}
 	vector<array<int,3>>edges;
 	vector<pair<int,int>>vec;
 	for(int i = 1; i <= m; i++) {
 		int u,v,w;
 		cin >> u >> v >> w;
 		vec.pb({u,v});
 		g[u].pb({v,w});
 		g[v].pb({u,w});
 	}
 	int k;
 	cin >> k;
 	priority_queue<pair<long long,int>,vector<pair<long long,int>>,greater<pair<long long,int>>>pq;
 	for(int i = 1; i <= k; i++) {
 		int x;
 		cin >> x;
 		mark[x] = true;
 		pq.push({0,x});
 		dist[x] = 0;
 	}
 	while(!pq.empty()) {
 		long long dst = pq.top().F;
 		int u = pq.top().S;
 		pq.pop();
 		for(auto X : g[u]) {
 			if(dist[X.F] > dst + X.S) {
 				dist[X.F] = dst + X.S;
 				pq.push({dist[X.F],X.F});
 			}
 		}
 	}
 	for(auto X : vec) {
 		int w = min(dist[X.F],dist[X.S]);
 		edges.pb({X.F,X.S,w});
 	}
 	sort(edges.begin(),edges.end(),cmp);
 	for(auto X : edges) {
 		if(!same(X[0],X[1])) {
 			graf[X[0]].pb({X[1],X[2]});
 			graf[X[1]].pb({X[0],X[2]});
 			unite(X[0],X[1]);
 		}
 	}
 	dfs(1,0);
 	int q;
 	cin >> q;
 	while(q--) {
 		int u,v;
 		cin >> u >> v;
		int LCA = lca(u,v);
		cout << min(get(u,LCA),get(v,LCA)) << "\n";
 	}
    return 0;
}

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