Submission #231617

#	Time	Username	Problem	Language	Result	Execution time	Memory
231617		_7_7_	Olympic Bus (JOI20_ho_t4)	C++14	0 / 100	44 ms	10488 KiB

ho_t4

#include <bits/stdc++.h>                                           
 
#define int long long
//#pragma GCC optimize("Ofast")
//#pragma comment(linker, "/stack:200000000")
//#pragma GCC target("sse,sse2,sse3,ssse3,sse4")
 
 
#define file(s) freopen(s".in","r",stdin); freopen(s".out","w",stdout);
#define forev(i, b, a) for(int i = (b); i >= (a); --i)
#define forn(i, a, b) for(int i = (a); i <= (b); ++i)
#define all(x) x.begin(), x.end()
#define sz(s) (int)s.size()
#define pb push_back
#define ppb pop_back
#define mp make_pair
#define s second
#define f first
 
 
using namespace std;
 
 
typedef pair < long long, long long > pll;    
typedef pair < int, int > pii;
typedef unsigned long long ull;         
typedef vector < pii > vpii;
typedef vector < int > vi;
typedef long double ldb;  
typedef long long ll;  
typedef double db;                             
 
 
const int inf = 1e9, maxn = 208, mod = 1e9 + 7, N = 5e4 + 11;
const int dx[] = {1, -1, 0, 0}, dy[] = {0, 0, 1, -1}, block = 555;
const pii base = mp(1171, 3307), Mod = mp(1e9 + 7, 1e9 + 9);
const db eps = 1e-12, pi = 3.14159265359;
const ll INF = 1e18;
 
int n, m, a[N], b[N], c[N], d[N], p[maxn], Bad, F[maxn][maxn], D[maxn];
vpii g[2][maxn];
set < pii > q;
bool I[maxn];
 
 
void Floyd () {
	for (int i = 1; i <= n; ++i)
		for (int j = 1; j <= n; ++j)	
		    if (i != j)
				F[i][j] = INF;
 
	for (int i = 1; i <= m; ++i)
		F[a[i]][b[i]] = min(F[a[i]][b[i]], c[i]);
 
	for (int k = 1; k <= n; ++k)
		for (int i = 1; i <= n; ++i)
			for (int j = 1; j <= n; ++j)
				F[i][j] = min(F[i][j], F[i][k] + F[k][j]);
 
}
 
int Dijkstra (int s, int f, int j) {
	memset(p, -1, sizeof(p));
	for (int i = 1; i <= n; ++i)
		D[i] = INF;

	D[s] = 0;
	q.insert({0ll, s});
	while (sz(q)) {
		int v = q.begin()->s;
		q.erase(q.begin());
		for (auto X : g[j][v]) {			
			int to = X.f, i = X.s;
			if (i != Bad && D[to] > D[v] + c[i]) {
				q.erase(mp(D[to], to));
				D[to] = D[v] + c[i];
				p[to] = i;
				q.insert(mp(D[to], to));
			}
		}
	}

/*	for (int i = 1; i <= n; ++i)
		cerr << p[i] << ' ';
	cerr << endl;*/

	if (!Bad) {
		for (int i = 1; i <= n; ++i)
			if (p[i] > -1)
				I[p[i]] = 1;
	}

	return D[f];
}
 
 
main () {
	scanf("%lld%lld", &n, &m);
	for (int i = 1; i <= m; ++i) {
		scanf("%lld%lld%lld%lld", &a[i], &b[i], &c[i], &d[i]);
		g[0][a[i]].pb({b[i], i});
		g[1][b[i]].pb({a[i], i});
	}
 
	Floyd();
	Dijkstra(1, n, 0);
	Dijkstra(n, 1, 0);
	Dijkstra(1, n, 1);
	Dijkstra(n, 1, 1);
 

	int ans = min(INF, F[1][n] + F[n][1]);
	for (int i = 1; i <= m; ++i) {
		if (I[i]) {
			Bad = i;
			g[0][b[i]].pb({a[i], m + 1});
			c[m + 1] = c[i];
			ans = min(ans, Dijkstra(1, n, 0) + Dijkstra(n, 1, 0) + d[i]);
			g[0][b[i]].ppb();
		} else {
			int d1 = min(F[1][n], F[1][b[i]] + F[a[i]][n] + c[i] + d[i]);
			int d2 = min(F[n][1], F[n][b[i]] + F[a[i]][1] + c[i] + d[i]);
			ans = min(ans, d1 + d2);
		}
	}
 
	if (ans == INF)
		ans = -1;
	printf("%lld\n", ans);			
}

Compilation message (stderr)

ho_t4.cpp:97:7: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type]
 main () {
       ^
ho_t4.cpp: In function 'int main()':
ho_t4.cpp:98:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%lld%lld", &n, &m);
  ~~~~~^~~~~~~~~~~~~~~~~~~~
ho_t4.cpp:100:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   scanf("%lld%lld%lld%lld", &a[i], &b[i], &c[i], &d[i]);
   ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

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