BZOJ1576 （最短路+并查集）

#include <cstdio>
#include <cstring>
#include <algorithm>
#include <queue>
#define inline __attribute__((optimize("O2")))
using namespace std;
   
#define maxn 100008
#define maxm 1000008
#define INF 2000000000
#define pa pair<int,int>
 
struct line{
    int u,v,w,nt;
}eg[maxm],E[maxm],e[maxm];
   
int lt[maxn],fa[maxn],n,m,sum=1,num=0,f[maxn],ans[maxn];
int d[maxn],pd[maxn];
   
inline void add(int u,int v,int w){
    eg[++sum].v=v; eg[sum].w=w; eg[sum].nt=lt[u]; lt[u]=sum;
}
inline void read(int &x){
    char ch;
    for (ch=getchar();ch<'0'||ch>'9';ch=getchar()); x=ch-48;
    for (ch=getchar();ch>='0'&&ch<='9';ch=getchar()) x=x*10+ch-48;
}
   
/*inline void spfa(){
    for (int i=1;i<=n;i++) d[i]=INF;
    queue<int> Q;
    memset(pd,0,sizeof(pd));
    pd[1]=1; d[1]=0; Q.push(1);
    while (!Q.empty()){
        int u=Q.front();
        for (int i=lt[u];i;i=eg[i].nt){
            int v=eg[i].v;
            if (d[u]+eg[i].w<d[v]){
                d[v]=d[u]+eg[i].w;
                fa[v]=u;
                if (!pd[v]){
                    Q.push(v);
                    pd[v]=1;
                }
            }
        }
        pd[u]=0;
        Q.pop();
    }
}*/
 
inline void dijkstra(){
    priority_queue<pa,vector<pa>,greater<pa> > Q;
    memset(pd,0,sizeof(pd));
    for (int i=1;i<=n;i++) d[i]=INF;
    d[1]=0; Q.push(make_pair(0,1));
    while (!Q.empty()){
        int u=Q.top().second; Q.pop();
        if (pd[u]) continue; pd[u]=1;
        for (int i=lt[u];i;i=eg[i].nt)
            if (d[u]+eg[i].w<d[eg[i].v]){
                d[eg[i].v]=d[u]+eg[i].w;
                fa[eg[i].v]=u;
                Q.push(make_pair(d[eg[i].v],eg[i].v));
            }
    }
}
   
inline bool cmp(line i,line j){
    return i.w<j.w;
}
   
inline int find(int x){ return f[x]==x?x:f[x]=find(f[x]); }
   
inline void work(int u,int v,int w){
    int x=find(u),y=find(v);
    while (x!=y){
        if (d[x]<d[y]) swap(x,y);
        ans[x]=w-d[x];
        num++;
        f[x]=fa[x];
        x=find(f[x]);
    }
}
   
inline int main(){
    read(n); read(m);
    int x,y,z;
    for (int i=1;i<=m;i++){
        read(x); read(y); read(z);
        add(x,y,z); add(y,x,z);
        e[i].u=x; e[i].v=y; e[i].w=z;
    }
    dijkstra();
    int cnt=0;
    for (int i=1;i<=m;i++){
        int u=e[i].u,v=e[i].v,w=e[i].w;
        if (fa[u]!=v && fa[v]!=u){
            E[++cnt].u=u;
            E[cnt].v=v;
            E[cnt].w=d[u]+d[v]+w;
        }
    }
    sort(E+1,E+cnt+1,cmp);
    for (int i=1;i<=n;i++) { ans[i]=-1; f[i]=i; }
    for (int i=1;i<=cnt;i++){
        work(E[i].u,E[i].v,E[i].w);
        if (num==n-1) break;      
    }
    for (int i=2;i<=n;i++) printf("%d
",ans[i]);
}