hdu 6166(随机概率dijkstra)

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题意：要你在一个图指定点钟找出两个距离最短的点

分析：枚举位数，使包含当前位数的为一个集合，不包含的为另一个集合，跑dijkstra

#include <cstdio>#include <queue>#include <algorithm>#include <cstring>#include <vector>#include <iostream>using namespace std;#define maxn 100400#define INF (1<<30)typedef long long int ll;typedef pair<int,int> P;int T;int n , m;bool vis[maxn];vector<P>E[maxn];int ans;int k ;int kx[maxn];bool mark[maxn];int d[maxn];priority_queue<P,vector<P>,greater<P> >Q;int dijkstra(){    while( !Q.empty() )    {        int c = Q.top().first;        int u = Q.top().second;        Q.pop();        if( !mark[u] && vis[u] ){            return c;        }        if( c > d[u] )continue;        for(int  i = 0 ; i < E[u].size() ; ++i)        {            int v = E[u][i].first;            int w = E[u][i].second;            if(d[v] > d[u] + w)            {                d[v] = d[u] + w;                Q.push(P(d[v],v));            }        }    }    return 1e9;}void init(){     while(!Q.empty())Q.pop();     for(int i = 0 ; i <= n ; ++i)d[i] = INF;     for(int i = 1 ; i <= n ; ++i)if( mark[i] )d[i] = 0 , Q.push(P(0,i));}int main(){    cin >> T;    int cas = 0;    while( T-- )    {        cin >> n >> m;        memset(vis,0,sizeof(vis));        for(int i = 0 ; i <= n ; ++i)E[i].clear();        for(int i = 0 ; i < m ; ++i)        {           int a,b,c;            scanf("%d %d %d",&a,&b,&c);            E[a].push_back(P(b,c));        }        cin >> k;        for(int i = 0; i < k ; ++i)scanf("%d",kx+i),vis[kx[i]] = 1;        printf("Case #%d: ",++cas);        ans = 1e9;        for(int i = 1 ; i < 20 ; ++i)        {            memset(mark,0,sizeof(mark));            for(int j = 0 ; j < k ; ++j){                if( kx[j] & ( 1 << i ) ){                    mark[kx[j]] = 1;                }            }            init();            ans = min( ans , dijkstra() );            memset(mark,0,sizeof(mark));            for(int j = 0 ; j < k ; ++j){                if( !( kx[j] & ( 1 << i ) ) ){                     mark[kx[j]] = 1;                }            }            init();            ans = min( ans , dijkstra() );        }          cout << ans << endl;    }}

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