bfs+状态压缩求出所有的状态,然后由于第一个节点需要特殊处理,可以右移一位剔除掉,也可以特判。然后采用集合的操作,
#pragma comment(linker,"/STACK:1024000000,1024000000")
#include <cstdio>
#include <queue>
using namespace std;
#define inf 0x3f3f3f3f int n, m, cnt;
int head[17], next[17 * 17 * 2 + 3][3], dp[1 << 17][17], dis[1 << 17], num[1 << 17]; void add (int u, int v, int w)
{
next[cnt][1] = v;
next[cnt][2] = w;
next[cnt][0] = head[u];
head[u] = cnt++;
} void bfs ()
{
queue<pair<int, int> > q;
q.push(make_pair(0, 1));
dp[1][0] = 0;
while (!q.empty()){
pair<int, int> p = q.front();
q.pop();
int su = p.second;
int u = p.first;
for (int i = head[u]; i != -1; i = next[i][0]){
int v = next[i][1];
int w = next[i][2];
int sv = su|(1 << v);
if(dp[sv][v] > dp[su][u] + w){
dp[sv][v] = dp[su][u] + w;
q.push(make_pair(v, sv));
}
}
}
} int main ()
{
//freopen ("in.txt", "r", stdin);
int t, count = 0;
scanf ("%d", &t);
while (t--)
{
scanf ("%d %d", &n, &m);
int u, v, w;
for (int i = 0; i < n; ++i) head[i] = -1;
for (int i = (1 << n) - 1; i >= 0; --i){
dis[i] = inf;
num[i] = inf;
for (int j = 0; j < n; ++j) dp[i][j] = inf;
}
cnt = 0;
for (int i = 0; i < m; ++i){
scanf ("%d %d %d", &u, &v, &w);
add (u - 1, v - 1, w);
add (v - 1, u - 1, w);
}
scanf ("%d", &m);
v = 0;
for (int i = 0; i < m; ++i){
scanf ("%d", &u);
v |= (1 << (u - 1));
}
v >>= 1;
if (!m || (m == 1 && u == 1)){
printf("Case %d: 0\n", ++count);
continue;
}
bfs ();
u = inf;
w = (1 << (n-1)) - 1;
for(int i = 1; i < (1 << n); ++i)
for(int j = 0; j < n; ++j)
dis[i >> 1] = min(dis[i >> 1], dp[i][j]);
for (int i = 1; i <= w; ++i)
for (int j = i; j; j = (j - 1) & i)
num[i] = min(num[i], max(dis[j], dis[i ^ j]));
for (int i = 1; i <= w; ++i)
for(int j = i; j; j = (j - 1) & i)
if((i & v) == v) u = min(u, max(num[j], dis[i ^ j]));
if (u == inf) u = -1;
printf("Case %d: %d\n", ++count, u);
}
return 0;
}