Submission #1129489

#	Time	Username	Problem	Language	Result	Execution time	Memory
1129489		zhasyn	Evacuation plan (IZhO18_plan)	C++20	35 / 100	1055 ms	61140 KiB

plan

#include <bits/stdc++.h>
#define pb push_back
#define pf push_front
using namespace std;
#define F first
#define S second
typedef long long ll;
#define pii pair <int, int>
#define pll pair <ll, ll>
typedef long double ld;
const ll N = 2 * 1e5 + 100, M = 500 + 10, len = 315, inf = 1e18;
const ll mod = 998244353;
ll um(ll a, ll b){
	return (1LL * a * b) % mod;
}
ll subr(ll a, ll b){
	return ((1LL * a - b) % mod + mod) % mod;
}
ll bp(ll x, ll step){
	ll res = 1;
	while(step){
		if(step & 1) res = um(res, x);
		x = um(x, x);
		step /= 2;
	}
	return res;
}
ll inv(ll x){
	return bp(x, mod - 2);
}

int n, m, k, d[N], p[N], sz[N];
vector <pii> q[N], qr[N];
void bfs(int x){
	set <pii> st;
	d[x] = 0;
	st.insert({d[x], x});
	while((int)st.size() != 0){
		int v = st.begin()->S;
		st.erase(st.begin());
		for(auto u : q[v]){
			if(d[u.F] > d[v] + u.S){
				d[u.F] = d[v] + u.S;
				st.insert({d[u.F], u.F});
			}
		}
	}
}
int tin[N], tout[N], timer, up[N][25], mn[N][25];
vector <pii> rev[N];
void dfs(int v, int p, int from){
	tin[v] = ++timer;
	up[v][0] = p;
	mn[v][0] = from;
	for(int i = 1; i <= 20; i++){
		up[v][i] = up[up[v][i - 1]][i - 1];
		mn[v][i] = min(mn[v][i - 1], mn[up[v][0]][i - 1]);
	}
	for(auto u : rev[v]){
		if(u.F == p) continue;
		dfs(u.F, v, u.S);
	}
	tout[v] = timer;
}
bool upper(int a, int b){
	return tin[a] <= tin[b] && tout[b] <= tout[a];
}
int lca(int a, int b){
	if(upper(a, b)) swap(a, b);
	int ans = INT_MAX;
	if(upper(b, a)){
		for(int i = 20; i >= 0; i--){
			if(up[a][i] == 0) continue;
			if(upper(up[a][i], b) == false){
				ans = min(ans, mn[a][i]);
				a = up[a][i];
			}
		}
		return min(ans, mn[a][0]);
	}
	for(int i = 20; i >= 0; i--){
		if(up[a][i] == 0) continue;
		if(upper(up[a][i], b) == false){
			ans = min(ans, mn[a][i]);
			a = up[a][i];
		}
	}
	for(int i = 20; i >= 0; i--){
		if(up[b][i] == 0) continue;
		if(upper(up[b][i], a) == false){
			ans = min(ans, mn[b][i]);
			b = up[b][i];
		}
	}
	return min(ans, min(mn[a][0], mn[b][0]));
}
int get(int x){
	if(x == p[x]) return x;
	else return p[x] = get(p[x]);
}
void addthem(ll a, ll b, ll x){
	int oa = a, ob = b;
	a = get(a);
	b = get(b);
	if(a != b){
		rev[oa].pb({ob, x});
		rev[ob].pb({oa, x});
		if(sz[b] > sz[a]) swap(a, b);
		sz[a] += sz[b];
		p[b] = a;
	}
}
int main() {
	//ios_base::sync_with_stdio(false);
	//cin.tie(nullptr);
	//cout.tie(nullptr);
	cin >> n >> m;
	for(int i = 0, a, b, c; i < m; i++){
		cin >> a >> b >> c;
		q[a].pb({b, c});
		q[b].pb({a, c});
	}
	for(int i = 1; i <= n; i++){
		d[i] = INT_MAX;
		p[i] = i;
		sz[i] = 1;
	}
	cin >> k;
	for(int i = 0, x; i < k; i++){
		cin >> x;
		bfs(x);
	}
	vector <pair <int, pii>> vec;
	for(int i = 1; i <= n; i++){
		for(auto u : q[i]){
			if(i > u.F) vec.pb({-min(d[u.F], d[i]), {i, u.F}});
		}
	}
	sort(vec.begin(), vec.end());
	for(auto u : vec){
		addthem(u.S.F, u.S.S, -u.F);
	}
	dfs(1, 0, INT_MAX);
	// for(int i = 1; i <= n; i++){
		// for(auto u : rev[i]){
			// cout << i << " "<< u.F << " " << -u.S << endl;
		// }
	// }
	int quer;
	cin >> quer;
	for(int i = 0, a, b; i < quer; i++){
		cin >> a >> b;
		cout << lca(a, b) << endl;
	}
  return 0;
}

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