【HDU】3768 Shopping 最短路+DP

传送门：【HDU】3768 Shopping

题目分析：羞愧死了。。。竟然把优先队列敲错了还没有发现。。。。。spfa轻松抢第一~~

首先最短路预处理出所有的商店到家以及其他商店的最短路，然后就是TSP形式的dp了。

真是的。。。早知道写spfa了。。。纠结了这么久还以为dp写错了。。

代码如下：

#include <cstdio>#include <cstring>#include <algorithm>using namespace std ;#define REP( i , a , b ) for ( int i = ( a ) ; i < ( b ) ; ++ i )#define FOR( i , a , b ) for ( int i = ( a ) ; i <= ( b ) ; ++ i )#define REV( i , a , b ) for ( int i = ( a ) ; i >= ( b ) ; -- i )#define travel( e , H , u ) for ( Edge* e = H[u] ; e ; e = e -> next )#define CLR( a , x ) memset ( a , x , sizeof a )const int MAXN = 100005 ;const int MAXH = 200005 ;const int MAXE = 200005 ;const int INF = 0x3f3f3f3f ;struct Edge {int v , c ;Edge* next ;} ;struct Heap {int v , idx ;Heap () {}Heap ( int v , int idx ) : v ( v ) , idx ( idx ) {}bool operator < ( const Heap& a ) const {return v < a.v ;}} ;struct priority_queue {Heap h[MAXH] ;int point ;priority_queue () : point ( 1 ) {}void clear () {point = 1 ;}void maintain ( int o ) {int p = o , l = o << 1 , r = o << 1 | 1 ;while ( o > 1 && h[o] < h[o >> 1] ) {swap ( h[o] , h[o >> 1] ) ;o >>= 1 ;}o = p ;while ( o < point ) {if ( l < point && h[l] < h[p] ) p = l ;if ( r < point && h[r] < h[p] ) p = r ;if ( p == o ) break ;swap ( h[o] , h[p] ) ;o = p , l = o << 1 , r = o << 1 | 1 ;}}void push ( int v , int idx ) {h[point] = Heap ( v , idx ) ;maintain ( point ++ ) ;}void pop () {h[1] = h[-- point] ;maintain ( 1 ) ;}bool empty () {return point == 1 ;}int front () {return h[1].idx ;}} ;struct Shortest_Path_Algorithm {priority_queue q ;Edge E[MAXE] , *H[MAXN] , *cur ;int d[MAXN] ;bool vis[MAXN] ;int Q[MAXN] , head , tail ;void init () {cur = E ;CLR ( H , 0 ) ;}void addedge ( int u , int v , int c ) {cur -> v = v ;cur -> c = c ;cur -> next = H[u] ;H[u] = cur ++ ;}void dijkstra ( int s ) {q.clear () ;CLR ( vis , 0 ) ;CLR ( d , INF ) ;d[s] = 0 ;q.push ( d[s] , s ) ;while ( !q.empty () ) {int u = q.front () ;q.pop () ;if ( vis[u] ) continue ;vis[u] = 1 ;travel ( e , H , u ) {int v = e -> v , c = e -> c ;if ( d[v] > d[u] + c ) {d[v] = d[u] + c ;q.push ( d[v] , v ) ;}}}}void spfa ( int s ) {head = tail = 0 ;CLR ( d , INF ) ;CLR ( vis , 0 ) ;d[s] = 0 ;Q[tail ++] = s ;while ( head != tail ) {int u = Q[head ++] ;if ( head == MAXN ) head = 0 ;vis[u] = 0 ;travel ( e , H , u ) {int v = e -> v , c = e -> c ;if ( d[v] > d[u] + c ) {d[v] = d[u] + c ;if ( !vis[v] ) {vis[v] = 1 ;if ( d[v] < d[Q[head]] ) {if ( head == 0 ) head = MAXN ;Q[-- head] = v ;} else {Q[tail ++] = v ;if ( tail == MAXN ) tail = 0 ;}}}}}}} G ;int dist[10][11] ;int store[11] ;int dp[1 << 10][10] ;void scanf ( int& x , char c = 0 ) {while ( ( c = getchar () ) < '0' || c > '9' ) ;x = c - '0' ;while ( ( c = getchar () ) >= '0' && c <= '9' ) x = x * 10 + c - '0' ;}void solve () {int n , m , s ;int u , v , c ;G.init () ;scanf ( n ) ;scanf ( m ) ;while ( m -- ) {scanf ( u ) , scanf ( v ) , scanf ( c ) ;G.addedge ( u , v , c ) ;G.addedge ( v , u , c ) ;}scanf ( s ) ;REP ( i , 0 , s ) scanf ( store[i] ) ;store[s] = 0 ;REP ( i , 0 , s ) {G.spfa ( store[i] ) ;FOR ( j , 0 , s ) dist[i][j] = G.d[store[j]] ;}int tot = 1 << s ;CLR ( dp , INF ) ;REP ( i , 0 , s ) dp[1 << i][i] = dist[i][s] ;REP ( i , 0 , tot )REP ( j , 0 , s )if ( dp[i][j] != INF )REP ( k , 0 , s )dp[i | ( 1 << k )][k] = min ( dp[i | ( 1 << k )][k] , dp[i][j] + dist[j][k] ) ;int ans = INF ;REP ( i , 0 , s ) ans = min ( ans , dp[tot - 1][i] + dist[i][s] ) ;printf ( "%d\n" , ans ) ;}int main () {int T ;scanf ( T ) ;while ( T -- ) solve () ;return 0 ;}