POJ 1511 Invitation Cards

标签：poj   spfa   dijkstra   heap   

SPFA + vector邻接表 居然TLE。 Time Limit: 8000MS

然后又是尝试一下 堆优化的Dijkstra + vector邻接表 果然还是TLE。

放弃vector，转为静态。

SPFA 1891MS

Dijkstra_heap 1938MS

突然发现以前做过这个题。搜一下自己的Blog SPFA + vector 7063MS 危险的过了……想不通了。。。

Dijkstra_heap

#include<cstdio>
#include<cstring>
#include<string>
#include<queue>
#include<algorithm>
#include<map>
#include<stack>
#include<iostream>
#include<list>
#include<set>
#include<bitset>
#include<vector>
#include<cmath>

#define INF 0x7fffffff
#define eps 1e-8
#define LL long long
#define PI 3.141592654
#define CLR(a,b) memset(a,b,sizeof(a))
#define FOR(i,a,b) for(int i=a;i<b;i++)
#define FOR_(i,a,b) for(int i=a;i>=b;i--)
#define pub push_back
#define puf push_front
#define pob pop_back
#define pof pop_front
#define mp make_pair
#define ft first
#define sd second
#define sf scanf
#define pf printf
#define sz(v) ((int)(v).size())
#define all(v) (v).begin(),(v).end()
#define acfun std::ios::sync_with_stdio(false)

#define SIZE 1000000 +1
using namespace std;

int head1[SIZE];
int head2[SIZE];
int n,m;
int cot1,cot2;
struct lx
{
    int v,l,next;
    void init(int vv,int ll,int nn)
    {
        v=vv,l=ll,next=nn;
    }
};
lx edge1[SIZE];
lx edge2[SIZE];

void add(int u,int v,int l)
{
    edge1[cot1].init(v,l,head1[u]);
    head1[u]=cot1++;
    edge2[cot2].init(u,l,head2[v]);
    head2[v]=cot2++;
}
void show(int *head,lx *edge)
{
    FOR(i,1,n+1)
    {
        int tmp=head[i];
        while(tmp!=-1)
        {
            pf("%d->%d=%d ",i,edge[tmp].v,edge[tmp].l);
            tmp=edge[tmp].next;
        }
        pf("\n");
    }
}

struct node
{
    int s,l;
    node(int ss,int ll)
    {
        s=ss,l=ll;
    }
    friend bool operator <(node a,node b)
    {
        if(a.l==b.l)return a.s<b.s;
        return a.l<b.l;
    }
};
int dis[SIZE];
LL Dijkstra(int *head,lx *edge)
{
    priority_queue<node>q;
    FOR(i,0,n+1)
    dis[i]=INF;
    dis[1]=0;
    q.push(node(1,dis[1]));
    while(!q.empty())
    {
        node tmp=q.top();
        q.pop();

        int u=tmp.s;
        dis[u]=tmp.l;

        int next=head[u];
        while(next!=-1)
        {
            int v=edge[next].v;
            int l=edge[next].l;
            if(dis[v]>dis[u]+l)
            {
                dis[v]=dis[u]+l;
                q.push(node(v,dis[v]));
            }
            next=edge[next].next;
        }
    }
    LL ans=0;
    FOR(i,1,n+1)
    ans+=dis[i];
    return ans;
}
int main()
{
    int t;
    sf("%d",&t);
    while(t--)
    {
        sf("%d%d",&n,&m);
        CLR(head1,-1);
        CLR(head2,-1);
        cot1=cot2=0;

        while(m--)
        {
            int u,v,l;
            sf("%d%d%d",&u,&v,&l);
            add(u,v,l);
        }
        //show(head1,edge1);
        LL ans=0;
        ans+=Dijkstra(head1,edge1);
        ans+=Dijkstra(head2,edge2);
        pf("%lld\n",ans);
    }
}

SPFA

#include<cstdio>
#include<cstring>
#include<string>
#include<queue>
#include<algorithm>
#include<map>
#include<stack>
#include<iostream>
#include<list>
#include<set>
#include<bitset>
#include<vector>
#include<cmath>

#define INF 0x7fffffff
#define eps 1e-8
#define LL long long
#define PI 3.141592654
#define CLR(a,b) memset(a,b,sizeof(a))
#define FOR(i,a,b) for(int i=a;i<b;i++)
#define FOR_(i,a,b) for(int i=a;i>=b;i--)
#define pub push_back
#define puf push_front
#define pob pop_back
#define pof pop_front
#define mp make_pair
#define ft first
#define sd second
#define sf scanf
#define pf printf
#define sz(v) ((int)(v).size())
#define all(v) (v).begin(),(v).end()
#define acfun std::ios::sync_with_stdio(false)

#define SIZE 1000000 +1
using namespace std;

int n,m;
int head1[SIZE],head2[SIZE];
int dis[SIZE];
bool vis[SIZE];
struct lx
{
    int v,l,next;
    void init(int vv,int ll,int nn)
    {
        v=vv,l=ll,next=nn;
    }
};
lx edge1[SIZE];
lx edge2[SIZE];
int cot1,cot2;

void add(int u,int v,int l)
{
    edge1[cot1].init(v,l,head1[u]);
    head1[u]=cot1++;
    edge2[cot2].init(u,l,head2[v]);
    head2[v]=cot2++;
}
void show(int *head,lx *edge)
{
    FOR(i,1,n+1)
    {
        int tmp=head[i];
        while(tmp!=-1)
        {
            pf("%d->%d=%d ",i,edge[tmp].v,edge[tmp].l);
            tmp=edge[tmp].next;
        }
        pf("\n");
    }
}
LL SPFA(int *head,lx *edge)
{
    FOR(i,0,n+1)
    dis[i]=INF;
    queue<int>q;
    CLR(vis,0);
    q.push(1);
    vis[1]=1;
    dis[1]=0;

    while(!q.empty())
    {
        int u=q.front();
        q.pop();
        vis[u]=0;

        int tmp=head[u];
        while(tmp!=-1)
        {
            int v=edge[tmp].v;
            int l=edge[tmp].l;
            if(dis[v]>dis[u]+l)
            {
                dis[v]=dis[u]+l;
                if(!vis[v])
                {
                    vis[v]=1;
                    q.push(v);
                }
            }
            tmp=edge[tmp].next;
        }
    }
    LL ans=0;
    FOR(i,1,n+1)
    ans+=dis[i];
    return ans;
}

int main()
{
    int t;
    sf("%d",&t);
    while(t--)
    {
        sf("%d%d",&n,&m);
        CLR(head1,-1);
        CLR(head2,-1);
        cot1=cot2=0;
        while(m--)
        {
            int u,v,l;
            sf("%d%d%d",&u,&v,&l);
            add(u,v,l);
        }
        //show(head1,edge1);
        LL ans=0;
        ans+=SPFA(head1,edge1);
        ans+=SPFA(head2,edge2);
        pf("%lld\n",ans);
    }
}

POJ 1511 Invitation Cards

标签：poj   spfa   dijkstra   heap   

原文地址：http://blog.csdn.net/dongshimou/article/details/41479509