Submission #1268636

#	Time	Username	Problem	Language	Result	Execution time	Memory
1268636		nhnguyen14	Olympic Bus (JOI20_ho_t4)	C++20	100 / 100	800 ms	2304 KiB

ho_t4

#include<bits/stdc++.h>
using namespace std;
typedef long long LL;

#define FOR(i,a,b) for(int i = (a) , _b = (b); i <= _b; ++i)
#define MASK(x) ((LL)(1) << (x))
#define BIT(mask , x) (((mask) >> (x)) & (1))
#define sz(x) (int)(x).size()
#define TIME_USED cerr << "\n Time lapsed : " << 1.0 * clock() / CLOCKS_PER_SEC << "s\n";

template<class T1 , class T2>
	bool maximize(T1 &a , T2 b){
		if (a < b) return a = b , true; else return false;
	}
template<class T1 , class T2>
	bool minimize(T1 &a , T2 b){
		if (a > b) return a = b , true; else return false;
	}
template<class T>
	void compress(vector<T>&data){
		sort(data.begin() , data.end());
		data.resize(unique(data.begin() , data.end()) - data.begin());
	}
template<class T1 , class T2>
	T2 Find(const vector<T1>&data , T2 y){
		return upper_bound(data.begin() , data.end() , y) - data.begin();
	}

const int N = (int) 200;
const int M  = (int) 5e4;
const LL inf = (LL)1e18;
	int x[M + 2] , y[M + 2] , c[M + 2] , d[M + 2];
	int n , m;

	vector<int> ke[N + 2][2];
		void add_canh(int u , int v , int id , int t){
			ke[u][t].push_back(id);
			return;
		}
		
	int belong_tree[M + 2] = {};
	int trace[N + 2] = {};
	bool ban[M + 2] = {};
		
	void djisktra(int source , int sink , int t , bool regis , LL dist[]){
		for(int i = 1; i <= n; ++i) dist[i] = inf;
		for(int i = 1; i <= n; ++i) trace[i] = false;
		priority_queue<pair<LL,int>,vector<pair<LL,int>>,greater<pair<LL,int>>>pq;
		dist[source] = 0;
		pq.push({dist[source] , source});
		while (pq.size()){
			int u = pq.top().second;
			LL cost = pq.top().first;
			pq.pop();
			if (cost != dist[u]) continue;
			for(int id : ke[u][!t]){
				if (ban[id] == false) continue;
				int v = u ^ x[id] ^ y[id];
				if (minimize(dist[v] , dist[u] + c[id])) {
					trace[v] = id;
					pq.push({dist[v] , v});
				}
			}
			for(int id : ke[u][t]){
				if (ban[id] == true) continue;
				int v = u ^ x[id] ^ y[id];
				if (minimize(dist[v] , dist[u] + c[id])) {
					trace[v] = id;
					pq.push({dist[v] , v});
				}
			}
		}
		for(int i = 1; i <= n; ++i) belong_tree[trace[i]] |= (regis & true);
		return;
	}
		
	LL dist[2][N + 2] = {};
	LL rev_dist[2][N + 2] = {};
	LL tmp[2][N + 2] = {};
		
int main(){
	ios::sync_with_stdio(false);
	cin.tie(0) ; cout.tie(0) ;
	#define name "main"
		if (fopen(name".inp","r")){
			freopen(name".inp","r",stdin);
			freopen(name".out","w",stdout);
		}
		
		cin >> n >> m;
		for(int i = 1; i <= m; ++i) {
			cin >> x[i] >> y[i] >> c[i] >> d[i];
			add_canh(x[i] , y[i] , i , 0);
			add_canh(y[i] , x[i] , i , 1);
		}
		djisktra(1 , n , 0 , 1 , dist[0]) , djisktra(1 , n , 1 , 1 , rev_dist[0]);
		djisktra(n , 1 , 0 , 1 , dist[1]) , djisktra(n , 1 , 1 , 1 , rev_dist[1]);
		LL ans = dist[0][n] + dist[1][1];
		
//		for(int i = 1; i <= n; ++i) cout << rev_dist[0][i] << ' ' ; cout << '\n';
		
		for(int i = 1; i <= m; ++i){
			if (belong_tree[i]){
				ban[i] = true;
					djisktra(1 , n , 0 , 0 , tmp[0]) , 
					djisktra(n , 1 , 0 , 0 , tmp[1]);
					LL cost = tmp[0][n] + tmp[1][1] + d[i];
					minimize(ans , cost);
				ban[i] = false;
			}
			else {
				int u = y[i] , v = x[i];
					LL cost1 = min({dist[0][n] , dist[0][u] + c[i] + rev_dist[1][v] , dist[0][v] + c[i] + rev_dist[1][u]});
					LL cost2 = min({dist[1][1] , dist[1][u] + c[i] + rev_dist[0][v] , dist[1][v] + c[i] + rev_dist[0][u]});
				minimize(ans , cost1 + cost2 + d[i]);
//				cout << i << ' ' << dist[0][n] << ' ' << cost2 + d[i] << '\n';
			}
		}
		if (ans >= inf) ans = -1;
		cout << ans;
		
	return 0;
}

Compilation message (stderr)

ho_t4.cpp: In function 'int main()':
ho_t4.cpp:86:32: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   86 |                         freopen(name".inp","r",stdin);
      |                         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~
ho_t4.cpp:87:32: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   87 |                         freopen(name".out","w",stdout);
      |                         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~

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