Submission #495137

#	Time	Username	Problem	Language	Result	Execution time	Memory
495137		mansur	Evacuation plan (IZhO18_plan)	C++14	100 / 100	906 ms	105124 KiB

plan

#include<bits/stdc++.h>	
 
/*
#pragma optimize ("g",on)
#pragma GCC optimize("inline")
#pragma GCC optimize ("Ofast")
#pragma GCC optimize ("unroll-loops")
#pragma GCC optimize ("03")
#pragma GCC target ("sse,sse2,sse3,ssse3,sse4,popcnt,abm,avx2,mmx,fma,avx,tune=native")
*/
 
//01001101 01100001 01101011 01101000 01100001  01100111 01100001 01111001 
 
using namespace std;
 
#define all(a) a.begin(), a.end()                                                   
#define rall(a) a.rbegin(), a.rend()
#define ll long long
#define pb push_back
#define sz(a) a.size()
#define nl '\n'
#define popb pop_back()                                                                   
#define ld double
#define ull unsigned long long
#define ff first                                         
#define ss second  
#define fix fixed << setprecision
#define pii pair<int, int>                          
#define E exit (0)
#define int long long
 
const int inf = 1e18, N = 2e5 + 1, mod = 998244353;                    
 
vector<pii> dir = {{1, 0}, {0, 1}, {-1, 0}, {0, -1}};
 
vector<pii> adj[N];

vector<int> d(N, inf), tin(N), tout(N);

pii up[N][20];

int p[N], l[N];

int timer;

int get(int x) {
	if (p[x] == x) return x;
	return p[x] = get(p[x]);
}

void calc(int u, int p = 1, int w = inf) {
	tin[u] = timer++;
	up[u][0] = {p, w};
	for (int i = 1; i < 18; i++) {
		up[u][i] = {up[up[u][i - 1].ff][i - 1].ff, min(up[u][i - 1].ss, up[up[u][i - 1].ff][i - 1].ss)};
	}
	for (auto e: adj[u]) {
		if (e.ff != p) {
			calc(e.ff, u, e.ss);	
		}
	}
	tout[u] = timer;
}

bool is(int u, int v) {
	return (tin[u] <= tin[v] && tout[u] >= tout[v]);
}

int lca(int u, int v) {
	if (is(u, v)) return u;
	if (is(v, u)) return v;
	for (int i = 17; i >= 0; i--) {
		int x = up[u][i].ff;
		if (is(x, v)) continue;
		u = x;
	}
	return up[u][0].ff;
}

int gett(int u, int v) {
	if (u == v) return d[u];
	int ans = inf;
	for (int i = 17; i >= 0; i--) {
		pii x = up[u][i];
		if (is(x.ff, v)) continue;
		u = x.ff;
		ans = min(ans, x.ss);
	}
	return min(ans, up[u][0].ss);
}

main() {                                                         
	//freopen("cowrect.in", "r", stdin);                                                                                     
	//freopen("cowrect.out", "w", stdout);                                                                                     
	ios_base::sync_with_stdio(NULL);                                                                                        
	cin.tie(NULL);
	int n, m;
	cin >> n >> m;
	for (int i = 1; i <= m; i++) {
		int u, v, w;
		cin >> u >> v >> w;
		adj[u].pb({v, w});
		adj[v].pb({u, w});
	}
	for (int i = 1; i <= n; i++) p[i] = i, l[i] = 1;
	int k;
	cin >> k;
	set<pii> s;
	for (int i = 1; i <= k; i++) {
		int a;
		cin >> a;
		s.insert({0, a});
		d[a] = 0;
	}
	while (!s.empty()) {
		int u = (*s.begin()).ss;
		s.erase(s.begin());
		for (auto e: adj[u]) {
			if (d[e.ff] > d[u] + e.ss) {
				s.erase({d[e.ff], e.ff});
				d[e.ff] = d[u] + e.ss;
				s.insert({d[e.ff], e.ff});
			}
		}
	}
	vector<pair<int, pii>> g;
	for (int i = 1; i <= n; i++) {
		for (auto e: adj[i]) {
			g.pb({min(d[e.ff], d[i]), {i, e.ff}});
		}
		adj[i].clear();
	}
	sort(rall(g));
	for (auto e: g) {
		int u = get(e.ss.ff), v = get(e.ss.ss);
		if (u != v) {
			if (l[u] > l[v]) swap(u, v);
			p[u] = v;
			l[v] += l[u];
			adj[e.ss.ff].pb({e.ss.ss, e.ff});
			adj[e.ss.ss].pb({e.ss.ff, e.ff});
		}
	}
	calc(1);
	int q;
	cin >> q;
	while (q--) {
		int u, v;
		cin >> u >> v;
		int lc = lca(u, v);
		cout << min(gett(u, lc), gett(v, lc)) << nl;
	}
}                    	        

Compilation message (stderr)

plan.cpp:92:1: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type]
   92 | main() {
      | ^~~~

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