CF303DIV2 E 迪斯特拉加堆优化

来源：互联网发布：如何扩大交际圈知乎编辑：程序博客网时间：2024/06/05 16:47
//首先这道题是卡没有优化的迪斯特拉的。。。。然后就是数据的溢出问题。。。都开long long吧
#include <iostream>#include<stdio.h>#include<algorithm>#include<string.h>#include<string>#include<queue>using namespace std;typedef long long ll;const int maxn=300000+10;const ll inf=99999999999999999;int head[maxn];int next[2*maxn];int to[2*maxn];ll val[2*maxn];int viss[maxn];int id[2*maxn];int ans[maxn];int tot;typedef long long ll;int inline read(){    int x=0,f=1;char ch=getchar();    while(ch<'0'||ch>'9'){if(ch=='-')f=-1;ch=getchar();}    while(ch>='0'&&ch<='9'){x=x*10+ch-'0';ch=getchar();}    return x*f;}struct heapnode{    ll d;    ll u;    heapnode()    {    }    heapnode(ll d1,ll u1):d(d1),u(u1)    {    }    bool operator <(const heapnode &rhs)const    {        return d>rhs.d;    }};void init(){    tot=0;    memset(head,-1,sizeof(head));}void inline addedge(int u,int v,ll value,int id1){    to[tot]=v;    val[tot]=value;    id[tot]=id1;    next[tot]=head[u];    head[u]=tot++;}int visit[maxn];ll low[maxn];int n;void inline dista(int start){    memset(visit,0,sizeof(visit));    ll sum=0;    int k=0;    low[start]=0;    priority_queue<heapnode>que;    heapnode x;    x.d=0;    x.u=start;    que.push(x);    while(!que.empty())    {        heapnode x=que.top();        que.pop();        if(visit[x.u])            continue;        visit[x.u]=1;        for(int i=head[x.u];i!=-1;i=next[i])        {            int v=to[i];            if(low[v]>low[x.u]+val[i])            {                low[v]=low[x.u]+val[i];                que.push(heapnode(low[v],v));            }        }    }}int main(){    int m;    init();    memset(viss,0,sizeof(viss));    scanf("%d%d",&n,&m);    for(int i=1;i<=m;i++)    {        int a,b,c;        a=(ll)read();        b=(ll)read();        c=(ll)read();        addedge(a,b,c,i);        addedge(b,a,c,i);    }    for(int i=1;i<=n;i++)        low[i]=inf;    int start;    scanf("%d",&start);    dista(start);    int k=0;    ll sum=0;    for(int i=1;i<=n;i++)    {        if(i!=start)        {            int pre=inf;            int pos;            for(int j=head[i];j!=-1;j=next[j])            {                int v=to[j];               // cout<<i<<" vvvv"<<v<<endl;              //  cout<<"low[i]  "<<low[i]<<" "<<low[v]<<" "<<val[j]<<endl;                if(low[v]+val[j]==low[i]&&val[j]<pre/*&&viss[id[j]]==0*/)                {                    pre=val[j];                    pos=id[j];                }            }            sum+=pre;            ans[k++]=pos;            //viss[pos]=1;        }    }    sort(ans,ans+k);    printf("%lld\n",sum);    for(int i=0;i<k;i++)    {        if(i!=k-1)            printf("%d ",ans[i]);        else            printf("%d\n",ans[i]);    }    return 0;}
0 0