UVA11367 Full Tank?

优先队列bfs

 1 #include<cmath>
 2 #include<queue>
 3 #include<cstdio>
 4 #include<string>
 5 #include<cstdlib>
 6 #include<cstring>
 7 #include<iostream>
 8 #include<algorithm>
 9 using namespace std;
10 #define rg register
11 typedef long long ll;
12 #define gmax(a,b) a=max(a,b)
13 #define FOR(i,a,b) for(rg int i=a;i<=b;++i)
14 #define qxx(i,a) for(rg int i=fir[a];i;i=nxt[i])
15 #define gc pa==pb&&(pb=(pa=buf)+fread(buf,1,100000,stdin),pa==pb)?EOF:*pa++
16 static char buf[100000],*pa(buf),*pb(buf);
17
18 inline int rd()
19 {
20   rg int x(0),w(1);
21   rg char ch(gc);
22   while(ch<'0' || ch>'9')
23     {
24       if(ch=='-') w=-1;
25       ch=gc;
26     }
27   while(ch>='0' && ch<='9') x=x*10+ch-48,ch=gc;
28   return x*w;
29 }
30
31 const int N=1010,M=10010,C=105,INF=99999999;
32 struct node
33 {
34   int u,cc,co;
35   node(int U,int CC,int CO){u=U;cc=CC;co=CO;}
36 };
37 bool operator < (node x,node y){return x.co>y.co;}
38 int f[N][C];
39 int pr[N],u[M<<1],v[M<<1],w[M<<1],fir[N],nxt[M<<1];
40 int n,m,tot,c,s,e;
41 priority_queue<node> q;
42
43 void bfs()
44 {
45   while(!q.empty()) q.pop();
46   q.push(node(s,0,0));
47   f[s][0]=0;
48   while(!q.empty())
49     {
50       node p=q.top();q.pop();
51       //cout<<p.u<<" "<<p.cc<<" "<<p.co<<endl;
52       if(p.u==e) {cout<<p.co<<endl;return;}
53       if(p.cc<c && p.co+pr[p.u]<f[p.u][p.cc+1])
54     {
55       f[p.u][p.cc+1]=p.co+pr[p.u];
56       q.push(node(p.u,p.cc+1,p.co+pr[p.u]));
57     }
58       qxx(i,p.u)
59     {
60       if(p.cc>=w[i] && f[v[i]][p.cc-w[i]]>=p.co)
61         {
62           f[v[i]][p.cc-w[i]]=p.co;
63           q.push(node(v[i],p.cc-w[i],p.co));
64         }
65     }
66     }
67   cout<<"impossible"<<endl;
68 }
69
70 int main()
71 {
72   n=rd(),m=rd();
73   FOR(i,1,n) pr[i]=rd();
74   while(tot<(m<<1))
75     {
76       u[++tot]=rd(),v[tot]=rd(),w[tot]=rd();
77       ++u[tot],++v[tot];
78       nxt[tot]=fir[u[tot]],fir[u[tot]]=tot;
79       ++tot;u[tot]=v[tot-1],v[tot]=u[tot-1],w[tot]=w[tot-1];
80       nxt[tot]=fir[u[tot]],fir[u[tot]]=tot;
81     }
82   int qq=rd();
83   FOR(i,1,qq)
84     {
85       memset(f,8,sizeof(f));
86       c=rd(),s=rd(),e=rd();
87       ++s,++e;
88       bfs();
89     }
90   return 0;
91 }