Submission #967514

#	Time	Username	Problem	Language	Result	Execution time	Memory
967514		thunopro	Cities (BOI16_cities)	C++14	100 / 100	1651 ms	72392 KiB

cities

#include<bits/stdc++.h>
using namespace std ; 
#define maxn 200009 
#define ll long long 
#define fi first 
#define se second 
#define pb push_back 
#define left id<<1
#define right id<<1|1 
#define _lower(x) lower_bound(v.begin(),v.end(),x)-v.begin()+1 
#define TIME (1.0*clock()/TIME_PERS_SEC) 
#define re exit(0); 

const int mod = 1e9+7 ; 
const int INF = 1e9 ; 

typedef vector<int> vi ; 
typedef pair<int,int> pii ; 
typedef vector<pii> vii ; 

void add ( int &a , int b ) 
{
	a += b ; 
	if ( a >= mod ) a -= mod ; 
	if ( a < 0 ) a += mod ; 
}

template < typename T > void chkmin ( T &a , T b ) { if ( a > b ) a = b ;} 
template < typename T > void chkmax ( T &a , T b ) { if ( a < b ) a = b ;} 

void rf () 
{
	freopen ("bai1.inp","r",stdin) ; 
}

mt19937 rng (time(0)) ; 

int _pow ( int a , int n ) 
{
	if ( n == 0 ) return 1 ; 
	int res = _pow (a,n/2) ; 
	if ( n % 2 ) return 1ll*res*res%mod*a%mod ; 
	else return 1ll*res*res%mod ; 
}
int n , k , m ; 
int imp [maxn] ; 
vii adjList [maxn] ; 

ll dp [34][maxn] ; 

struct shape {
	int u ; 
	ll d ; 
	bool operator < ( const shape &o ) const 
	{
		return d > o.d ; 
	}
};
void dijkstra ( ll dp [] ) 
{
	priority_queue<shape> S ; 
	for ( int i = 1 ; i <= n ; i ++ ) S . push ({i,dp[i]}) ; 
	while ( !S.empty() ) 
	{
		shape t = S.top() ; S.pop() ; 
		int u = t.u ; 
		for ( auto x : adjList [u] ) 
		{
			int v = x.fi , w = x.se ; 
			if ( dp [v] > dp [u] + w ) S . push ({v,dp[v]=dp[u]+w}) ; 
		}
	}
}
int main ()
{
	ios_base::sync_with_stdio(0); 
	cin.tie(0);cout.tie(0); 
//	rf () ; 
	cin >> n >> k >> m ; 
	for ( int i = 0 ; i < k ; i ++ ) cin >> imp [i] ; 
	for ( int i = 1 ; i <= m ; i ++ ) 
	{
		int u , v , w ; cin >> u >> v >> w ; 
		adjList [u] . pb ({v,w}) ; 
		adjList [v] . pb ({u,w}) ;
	}
		
	memset ( dp , 0x3f , sizeof dp ) ; 
	for ( int i = 0 ; i < k ; i ++ ) dp [1<<i][imp[i]] = 0 ; 

	for ( int mask = 1 ; mask < (1<<k) ; mask ++ ) 
	{
		for ( int i = 1 ; i <= n ; i ++ ) for ( int sub_mask = mask ; sub_mask ; sub_mask = (sub_mask-1)&mask ) 
		{
			chkmin (dp[mask][i],dp[sub_mask][i]+dp[mask^sub_mask][i]) ; 
		}
		dijkstra (dp[mask]) ; 
	}
	
	cout << *min_element(dp[(1<<k)-1] + 1 , dp[(1<<k)-1] + n) ; 
}

Compilation message (stderr)

cities.cpp: In function 'void rf()':
cities.cpp:33:10: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   33 |  freopen ("bai1.inp","r",stdin) ;
      |  ~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 22 / 22
• Subtask 2: 14 / 14
• Subtask 3: 15 / 15
• Subtask 4: 23 / 23
• Subtask 5: 26 / 26