Submission #1043372

#	Time	Username	Problem	Language	Result	Execution time	Memory
1043372		Minbaev	Commuter Pass (JOI18_commuter_pass)	C++17	100 / 100	320 ms	44332 KiB

commuter_pass

#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp> 
 
#pragma GCC target("avx,avx2,fma")
#pragma GCC optimize("Ofast,unroll-loops")
 
using namespace std;
using namespace __gnu_pbds;
 
#define pb push_back
#define all(x) x.begin(),x.end()
#define rall(x) x.rbegin(),x.rend()
#define f first
#define s second
#define int long long
#define ll long long
#define pii pair<int,int>
#define ar array
 
template<class T>bool umax(T &a,T b){if(a<b){a=b;return true;}return false;}
template<class T>bool umin(T &a,T b){if(b<a){a=b;return true;}return false;}
 
typedef tree<int, null_type, less_equal<int>, rb_tree_tag,
 tree_order_statistics_node_update> ordered_set;
 
const int inf = 1e17 + 7;
const int mod = 1e9 + 7;
const int N = 3e5 + 5;
const int md = 998244353;
 
int binpow(int a, int b){
	if(b == 0)return 1;
	if(b % 2 == 0){
		int c = binpow(a,b/2);
		return (c*c)%mod;
	}
	return (binpow(a,b-1)*a)%mod;
}
 
int divi(int a, int b){
	return (a*(binpow(b,mod-2)))%mod;
}
 
int n,m,k;
vector<pii>g[N];
vector<int>ds(N, inf);
bool visited[N];
int ans = inf;
int du[N], dv[N];
int dp[2][N];
 
void des(int y, int arr[]){
	for(int i = 1;i<=n;i++)arr[i] = inf;
	arr[y] = 0;
	priority_queue<pii, vector<pii>, greater<pii>>q;
	
	q.push({0, y});
	
	while(!q.empty()){
		auto [cost, x] = q.top();
		q.pop();
		
		if(arr[x] < cost)continue;
		for(auto [to,t] : g[x]){
			if(umin(arr[to], cost + t)){
				q.push({arr[to], to});
			}
		}
	}
}
 
void des2(int start, int end){
	fill(dp[0], dp[0] + 100001, LLONG_MAX / 2);
	fill(dp[1], dp[1] + 100001, LLONG_MAX / 2);
	fill(visited, visited + 100001, false);

	priority_queue<pair<ll, pair<ll, ll>>> pq;
	pq.push({0, {start, 0}});
	dp[0][0] = dp[1][0] = LLONG_MAX / 2;
	while (!pq.empty()) {
		ll c, node, par;
		pair<ll, ll> p;
		tie(c, p) = pq.top();
		tie(node, par) = p;
		pq.pop();

		if (!visited[node]) {
			visited[node] = true;
			ds[node] = -c;
			dp[0][node] = min(du[node], dp[0][par]);
			dp[1][node] = min(dv[node], dp[1][par]);
			for (auto i : g[node]) pq.push({c - i.second, {i.first, node}});
		} else if (-c == ds[node]) {
			if (min(du[node], dp[0][par]) + min(dv[node], dp[1][par]) <=
			    dp[0][node] + dp[1][node]) {
				dp[0][node] = min(du[node], dp[0][par]);
				dp[1][node] = min(dv[node], dp[1][par]);
			}
		}
	}

	ans = min(ans, dp[0][end] + dp[1][end]);
	
}
 
void solve(){
	
	cin >> n >> m;
	int a,b,c,d;
	cin >> a >> b >> c >> d;
	
	while(m--){
		int l,r,x;
		cin >> l >> r >> x;
		g[l].pb({r,x});
		g[r].pb({l,x});
	}
	
	des(c, du);
	des(d, dv);
	
	ans = du[d];
		
	des2(a, b);
	des2(b, a);
	
	//~ for(int i = 1;i<=n;i++)cout << du[i] << " ";
	cout << ans << "\n";
	
}
/*
 
*/
 signed main()
{
//	freopen("seq.in", "r", stdin);
//  freopen("seq.out", "w", stdout);
	ios_base::sync_with_stdio(0);cin.tie(NULL);cout.tie(NULL);
	int tt=1;//cin>>tt;
	while(tt--)solve();
 
}
 

• Subtask 1: 16 / 16
• Subtask 2: 15 / 15
• Subtask 3: 24 / 24
• Subtask 4: 45 / 45