Submission #1055180

#	Time	Username	Problem	Language	Result	Execution time	Memory
1055180		Alihan_8	Olympic Bus (JOI20_ho_t4)	C++17	5 / 100	1075 ms	4756 KiB

ho_t4

#include <bits/stdc++.h>

using namespace std;

#define all(x) x.begin(), x.end()
#define ar array
#define pb push_back
#define ln '\n'
#define int long long

using i64 = long long;

template <class F, class _S>
bool chmin(F &u, const _S &v){
    bool flag = false;
    if ( u > v ){
        u = v; flag |= true;
    }
    return flag;
}

template <class F, class _S>
bool chmax(F &u, const _S &v){
    bool flag = false;
    if ( u < v ){
        u = v; flag |= true;
    }
    return flag;
}

const int inf = 1e12;

signed main(){
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);
	
	int n, m; cin >> n >> m;
	
	vector <int> U(m), V(m), C(m), D(m);
	
	for ( int i = 0; i < m; i++ ){
		cin >> U[i] >> V[i] >> C[i] >> D[i];
		
		--U[i], --V[i];
	}
	
	auto f = [&](int s, int e){
		auto get = [&](auto U, auto V, auto C, int sx){
			vector <vector<ar<int,2>>> adj(n);
			
			for ( int i = 0; i < (int)U.size(); i++ ){
				adj[U[i]].pb({V[i], C[i]});
			}
			
			vector <int> dp(n, inf);
			
			priority_queue <ar<int,2>> q;
			
			q.push({0, sx}); dp[sx] = 0;
			
			while ( !q.empty() ){
				auto [val, u] = q.top();
				q.pop();
				
				if ( -val != dp[u] ) continue;
				
				for ( auto &[v, w]: adj[u] ){
					if ( chmin(dp[v], dp[u] + w) ){
						q.push({-dp[v], v});
					}
				}
			}
			
			return dp;
		};
		
		auto fs = get(U, V, C, s);
		auto fe = get(U, V, C, e);
		auto ts = get(V, U, C, s); 
		
		int opt = fs[e] + fe[s];
		
		return opt;
		
		for ( int i = 0; i < m; i++ ){
			if ( chmin(opt, fs[e] + fe[V[i]] + ts[U[i]] + D[i] + C[i]) ){
				//~ cout << opt << " -> " << fs[e] << " " << fe[V[i]] << " " << ts[U[i]] << ln;
			}
		}
		
		return opt;
	};
	
	int ans = f(0, n - 1);
	
	for ( int i = 0; i < m; i++ ){
		swap(U[i], V[i]);
		
		chmin(ans, f(0, n - 1) + D[i]);
		
		swap(U[i], V[i]);
	}
 	
	if ( ans >= inf ) ans = -1;
	
	cout << ans;
	
    cout << '\n';
}

• Subtask 1: 5 / 5
• Subtask 2: 0 / 11
• Subtask 3: 0 / 21
• Subtask 4: 0 / 63