Submission #1043357

#	Time	Username	Problem	Language	Result	Execution time	Memory
1043357		Minbaev	Commuter Pass (JOI18_commuter_pass)	C++17	15 / 100	177 ms	31992 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 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];
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 y, int i){
	vector<int>ds(N, inf);
	for(int l = 0;l<2;l++)
		for(int j = 0;j<=n;j++)
			dp[l][j] = inf;
	ds[y] = 0;
	
	priority_queue<array<int,3>, vector<array<int,3>>, greater<array<int,3>>>q;
	q.push({0,y,0});
	while(!q.empty()){
		auto [cost, x, pr] = q.top();
		q.pop();
		
		if(ds[x] < cost)continue;
		if(min(du[x], dp[0][pr]) + min(dv[x], dp[1][pr]) <= dp[0][x] + dp[1][x]){
			dp[0][x] = min(du[x], dp[0][pr]);
			dp[1][x] = min(dv[x], dp[1][pr]);
		}
		
		for(auto [to,t]: g[x]){
			if(umin(ds[to], cost + t)){
				q.push({ds[to], to, x});
			}
		}
	}
	
	
	
	umin(ans, dp[0][i] + dp[1][i]);
	
}

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: 0 / 16
• Subtask 2: 15 / 15
• Subtask 3: 0 / 24
• Subtask 4: 0 / 45