bzoj1576[Usaco2009 Jan]安全路径Travel（堆优化dijkstra+并查集）

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spfa会被卡。。
思想和3694差不多。
就是最短路树要自己跑dij建出来，其余的基本上一模一样。

#include<cstdio>#include<algorithm>#include<cstring>#include<iostream>#include<queue>#define fo(i,a,b) for(int i=a;i<=b;i++)#define fd(i,a,b) for(int i=a;i>=b;i--)using namespace std;const int N=5e5+5;int n,m;int tot,head[N],next[N],go[N],val[N],f[N],cnt;int fa[N],bel[N],dis[N],h[N];int vis[N],re[N];struct node{    int x,y,l,len;}edge[N],e[N];struct p{    int pt,v;    bool operator < (const p &x)const    {        return v>x.v;    }};priority_queue<p>q;inline void add(int x,int y,int z){    go[++tot]=y;    val[tot]=z;    next[tot]=head[x];    head[x]=tot;}inline void dij(){    memset(dis,0x7f,sizeof(dis));    dis[1]=0;    q.push((p){1,0});    while (!q.empty())    {        p now=q.top();        q.pop();        int x=now.pt;        for(int i=head[x];i;i=next[i])        {            int v=go[i];            if (dis[v]>dis[x]+val[i])            {                dis[v]=dis[x]+val[i];                h[v]=h[x]+1;                re[v]=i;                fa[v]=x;                q.push((p){v,dis[v]});            }        }    }}inline int find(int x){    if (x==f[x])return x;    else return f[x]=find(f[x]);}inline bool cmp(node a,node b){    return a.len<b.len;}int main(){    scanf("%d%d",&n,&m);    fo(i,1,m)    {        int x,y,z;        scanf("%d%d%d",&x,&y,&z);        add(x,y,z);        add(y,x,z);        e[i].x=x,e[i].y=y,e[i].l=z;    }    dij();    fo(i,2,n)vis[re[i]]=1;    fo(i,1,m)    if (!vis[i*2-1]&&!vis[i*2])    {        edge[++cnt].x=e[i].x;        edge[cnt].y=e[i].y;        edge[cnt].l=e[i].l;    }    fo(i,1,cnt)    edge[i].len=edge[i].l+dis[edge[i].x]+dis[edge[i].y];    sort(edge+1,edge+1+cnt,cmp);    fo(i,1,n)f[i]=i;    fo(i,1,cnt)    {        int x=edge[i].x,y=edge[i].y;        int fx=find(x),fy=find(y);        int lastx=0,lasty=0;        while (fx!=fy)        {            if (h[fx]<h[fy])swap(x,y),swap(fx,fy),swap(lastx,lasty);            if (!bel[x])            {                bel[x]=i;                if (lastx)f[lastx]=x;            }            else if (lastx)f[lastx]=x;            lastx=fx;            x=fa[lastx];            fx=find(x);        }    }    fo(i,2,n)    if (bel[i])printf("%d\n",edge[bel[i]].len-dis[i]);    else printf("-1\n");}

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