学步园

Dijkstra + Heap

Problem : 2544 ( 最短路 )     Judge Status : Accepted
RunId : 8360313    Language : G++    Author : CherryChou
Code Render Status : Rendered By HDOJ G++ Code Render Version 0.01 Beta

 

# include<cstdio>
# include<cstring>
# include<algorithm>
# include<queue>
# include<map>
# include<vector>
# include<utility>
using namespace std;

const int inf=1<<25;
const int maxn=105;
const int maxm=20005;
typedef pair<int,int> node;

struct edge
{
    int u,v,w,next;
} e[maxm];

struct cmp
{
    bool operator()(const node &a,const node &b)const
    {
        return a.second>b.second;
    }
};

int num,head[maxn];
int dis[maxn],n,m;
bool vis[maxn];
priority_queue<node,vector<node>,cmp> q;

inline void add(int u,int v,int w)
{
    e[num].u=u;
    e[num].v=v;
    e[num].w=w;
    e[num].next=head[u];
    head[u]=num++;
}
    
void addedge(int u,int v,int w)
{
    add(u,v,w);
    add(v,u,w);
} 

void dijkstra(int s)
{
    int i,u,v;
    dis[s]=0;
    q.push(make_pair(s,dis[s]));
    while(!q.empty())
    {
        u=q.top().first;
        q.pop();
        if(vis[u])
            continue;
        vis[u]=1;
        for(i=head[u];i!=-1;i=e[i].next)
        {
            v=e[i].v;
            if(!vis[v]&&dis[u]+e[i].w<dis[v])
            {
                dis[v]=dis[u]+e[i].w;
                q.push(make_pair(v,dis[v]));
            }
        }    
    }
}

void init()
{
    num=0;
    memset(head,-1,sizeof(head));
    memset(vis,0,sizeof(vis));
    for(int i=0;i<=n;i++)
    {
        dis[i]=inf;
        vis[i]=0;
    }
}

int main()
{
    while(~scanf("%d%d",&n,&m),n+m)
    {
        init();
        int s,t,w;
        while(m--)
        {
            scanf("%d%d%d",&s,&t,&w);
            addedge(s,t,w);
        }
        dijkstra(1);
        printf("%d\n",dis[n]);
    }
    return 0;
}

 

 

SPFA

 

Problem : 2544 ( 最短路 )     Judge Status : Accepted
RunId : 8360334    Language : G++    Author : CherryChou
Code Render Status : Rendered By HDOJ G++ Code Render Version 0.01 Beta

 

# include<cstdio>
# include<cstring>
# include<algorithm>
# include<queue>
using namespace std;

const int inf=1<<25;
const int maxn=105;
const int maxm=20005;
typedef pair<int,int> node;

struct edge
{
    int u,v,w,next;
} e[maxm];

int num,head[maxn];
int dis[maxn],n,m;
bool vis[maxn];
queue<int> q;

inline void add(int u,int v,int w)
{
    e[num].u=u;
    e[num].v=v;
    e[num].w=w;
    e[num].next=head[u];
    head[u]=num++;
}
    
void addedge(int u,int v,int w)
{
    add(u,v,w);
    add(v,u,w);
} 

void spfa(int s)
{
    int i,u,v;
    dis[s]=0;
    q.push(s);
    vis[s]=1;
    while(!q.empty())
    {
        u=q.front();
        q.pop();
        for(i=head[u];i!=-1;i=e[i].next)
        {
            v=e[i].v;
            if(dis[u]+e[i].w<dis[v])
            {
                dis[v]=dis[u]+e[i].w;
                if(!vis[v])
                {    
                        q.push(v);
                    vis[v]=1;
                }
            }
        }
        vis[u]=0;
    }
}

void init()
{
    num=0;
    memset(head,-1,sizeof(head));
    memset(vis,0,sizeof(vis));
    for(int i=1;i<=n;i++)
    {
        dis[i]=inf;
        vis[i]=0;
    }
}

int main()
{
    while(~scanf("%d%d",&n,&m),n+m)
    {
        init();
        int s,t,w;
        while(m--)
        {
            scanf("%d%d%d",&s,&t,&w);
            addedge(s,t,w);
        }
        spfa(1);
        printf("%d\n",dis[n]);
    }
    return 0;
}