【BZOJ】1097: [POI2007]旅游景点atr（spfa+状压dp）

#include <cstdio>
#include <cstring>
#include <cmath>
#include <string>
#include <iostream>
#include <algorithm>
#include <queue>
#include <set>
#include <map>
using namespace std;
typedef long long ll;
#define rep(i, n) for(int i=0; i<(n); ++i)
#define for1(i,a,n) for(int i=(a);i<=(n);++i)
#define for2(i,a,n) for(int i=(a);i<(n);++i)
#define for3(i,a,n) for(int i=(a);i>=(n);--i)
#define for4(i,a,n) for(int i=(a);i>(n);--i)
#define CC(i,a) memset(i,a,sizeof(i))
#define read(a) a=getint()
#define print(a) printf("%d", a)
#define dbg(x) cout << (#x) << " = " << (x) << endl
#define error(x) (!(x)?puts("error"):0)
#define rdm(x, i) for(int i=ihead[x]; i; i=e[i].next)
#define grdm(g, x, i) for(int i=g.ihead[x]; i; i=g.e[i].next)
inline const int getint() { int r=0, k=1; char c=getchar(); for(; c<‘0‘||c>‘9‘; c=getchar()) if(c==‘-‘) k=-1; for(; c>=‘0‘&&c<=‘9‘; c=getchar()) r=r*10+c-‘0‘; return k*r; }

const int N=50005, oo=0x3f3f3f3f;
int d[22][N], vis[N], q[N], ihead[N], cnt, n, m, k;
struct dat { int next, to, w; }e[N*10*2];
void add1(int u, int v, int w) { e[++cnt].next=ihead[u]; ihead[u]=cnt; e[cnt].to=v; e[cnt].w=w; }
void add(int u, int v, int w) { add1(u, v, w); add1(v, u, w); }
void spfa(int s, int *f) {
	memset(vis, 0, sizeof(int)*(n));
	memset(f, 0x3f, sizeof(int)*(n));
	int front=0, tail=0;
	f[s]=0; q[tail++]=s; vis[s]=1;
	while(front!=tail) {
		int u=q[front++], v; if(front==N) front=0; vis[u]=0;
		rdm(u, i) if(f[v=e[i].to]>f[u]+e[i].w) {
			f[v]=f[u]+e[i].w;
			if(!vis[v]) {
				vis[v]=1;
				if(f[q[front]]>f[v]) {
					--front; if(front<0) front+=N;
					q[front]=v;
				}
				else {
					q[tail++]=v; if(tail==N) tail=0;
				}
			}
		}
	}
}
int ans[21][1<<(20)], b[22], all;
int dfs(int u, int s) {
	if(ans[u][s]>=0) return ans[u][s];
	if(s==all) return d[u][n-1];
	int &a=ans[u][s]; a=oo;
	for1(v, 1, k) if((b[v]&s)==b[v]) a=min(a, d[u][v]+dfs(v, s|(1<<(v-1))));
	return a;
}
int main() {
	read(n); read(m); read(k);
	for1(i, 1, m) { int u=getint(), v=getint(), w=getint(); add(u-1, v-1, w); }
	for1(i, 0, k) spfa(i, d[i]);
	read(m);
	for1(i, 1, m) { int u=getint(), v=getint(); b[v-1]|=(1<<(u-2)); }
	all=(1<<k)-1;
	CC(ans, -1);
	printf("%d\n", dfs(0, 0));
	return 0;
}