bzoj4152 [AMPPZ2014]The Captain

　　最短路，先将x排序，然后把排序后权值相邻的点连边，再把y排序，也把权值相邻的点连边，求一遍1到n的最短路就好啦。

　　代码

 1 #include<cstdio>
 2 #include<queue>
 3 #include<algorithm>
 4 #define mp make_pair
 5 #define fi first
 6 #define sc second
 7 #define N 1000000
 8 using namespace std;
 9 typedef long long ll;
10 typedef pair<int,int> P;
11 int n,i,dp,p[N],pre[N],tt[N],ww[N],flag[N];
12 int dis[N];
13 priority_queue<P,vector<P>,greater<P> > Q;
14 struct g{
15     int a,b,id;
16 }v[N];
17 bool cmp1(g u,g v)
18 {
19     return u.a<v.a;
20 }
21 bool cmp2(g u,g v)
22 {
23     return u.b<v.b;
24 }
25 
26 void link(int x,int y,int z)
27 {
28     dp++;pre[dp]=p[x];p[x]=dp;tt[dp]=y;ww[dp]=z;
29 }
30 long long ans,f[N],sum[N];
31 int main()
32 {
33     scanf("%d",&n);
34     for (i=1;i<=n;i++)
35     scanf("%d%d",&v[i].a,&v[i].b),v[i].id=i;
36     sort(v+1,v+1+n,cmp1);
37     for (i=1;i<n;i++)
38     {
39         link(v[i].id,v[i+1].id,abs(v[i].a-v[i+1].a));
40         link(v[i+1].id,v[i].id,abs(v[i].a-v[i+1].a));
41     }
42     sort(v+1,v+1+n,cmp2);
43     for (i=1;i<n;i++)
44     {
45         link(v[i].id,v[i+1].id,abs(v[i].b-v[i+1].b));
46         link(v[i+1].id,v[i].id,abs(v[i].b-v[i+1].b));
47     }
48     int inf=1000000000;
49     for (i=2;i<=n;i++) dis[i]=inf;
50     Q.push(mp(0,1));
51     
52     while (!Q.empty())
53     {
54         P x=Q.top();Q.pop();
55         if (x.fi!=dis[x.sc]) continue;
56         i=p[x.sc];
57         while (i)
58         {
59             if (dis[x.sc]+ww[i]<dis[tt[i]])
60             {
61                 dis[tt[i]]=dis[x.sc]+ww[i];
62                 Q.push(mp(dis[tt[i]],tt[i]));
63             }
64             i=pre[i];
65         }
66     }
67     printf("%d\n",dis[n]);
68 }

posted @ 2016-04-24 21:43 fzmh 阅读(193) 评论(0) 收藏举报

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