Dijastra最短路 + 堆优化 模板

#include<algorithm>
#include<cstring>
#include<vector>
#include<map>
#include<cmath>
#include<cstdio>
#include<queue>
#include<iostream>
typedef long long ll;
const int mod = 1e9+7;
const int maxn = 1000000;
const int inf = 0x3f3f3f3f;
using namespace std;
/*dij堆优化*/ 
struct edge
{
    int to, dis, next;     
};

edge e[maxn];
int head[maxn], dis[maxn], cnt;
bool vis[maxn];
int n, m, s;

inline void add_edge( int u, int v, int d )
{
    cnt++;
    e[cnt].dis = d;
    e[cnt].to = v;
    e[cnt].next = head[u];
    head[u] = cnt;
}

struct node
{
    int dis;
    int pos;
    bool operator <( const node &x )const
    {
        return x.dis < dis;
    }
};

priority_queue<node> q;

inline void dijkstra(int start)
{
    dis[s] = 0;
    q.push( ( node ){0, s} );
    while( !q.empty() )
    {
        node tmp = q.top();
        q.pop();
        int x = tmp.pos ; 
        
        if( vis[x] )
        continue;
        vis[x] = 1;
        
        for( int i = head[x]; i; i = e[i].next )
        {
            int y = e[i].to;
            if( dis[y] > dis[x] + e[i].dis )
            {
                dis[y] = dis[x] + e[i].dis;
                if( !vis[y] )
                {
                    q.push( ( node ){dis[y], y} );
                }
            }
        }
    }
}

 
int main()
{
    cin>>n>>m>>s;
    for(int i = 1; i <= n; ++i)dis[i] = inf;
    
    for( register int i = 0; i < m; ++i )
    {
        register int u, v, d;
        cin>>u>>v>>d;        // u起点 v终点 d权重 
        add_edge( u, v, d );
    }
    
    dijkstra(s); //s为起点，dis[i]为 从起点到 i的最短路
    for( int i = 1; i <= n; i++ )
        cout<<dis[i]<<" ";
        cout<<endl; 
        
    return 0;
}

 

多组输入的初始化问题  

HDU 1874

#include<algorithm>
#include<cstring>
#include<vector>
#include<map>
#include<cmath>
#include<cstdio>
#include<queue>
#include<iostream>
typedef long long ll;
const int mod = 1e9+7;
const int maxn = 1000000;
const int inf = 0x3f3f3f3f;
using namespace std;
/*dij堆优化*/ 
struct edge
{
    int to, dis, next;   
};

edge e[maxn] = {0,0,0};

int head[maxn], dis[maxn], cnt;

bool vis[maxn];

int n, m, s;

inline void add_edge( int u, int v, int d )
{
    
    cnt++;
    e[cnt].dis = d;
    e[cnt].to = v;
    e[cnt].next = head[u];
    head[u] = cnt;
    
}

struct node
{
    
    int dis;
    int pos;
    bool operator < ( const node &x )const
    {
        return x.dis < dis;
    }
    
};

priority_queue<node> q;
void init()
{
    cnt = 0;
    memset(head,0,sizeof(head));
    memset(vis,0,sizeof(vis));
    memset(dis,inf,sizeof(dis));
    memset(e,0,sizeof(e));
}
inline void dijkstra(int start)
{
    dis[start] = 0;
    q.push( ( node ){0, start} );
    while( !q.empty() )
    {
        node tmp = q.top();
        
        q.pop();
        
        int x = tmp.pos ; 
        
        if( vis[x] )
        continue;
        
        vis[x] = 1;
        
        for( int i = head[x]; i; i = e[i].next )
        {
            int y = e[i].to;
            
            if( dis[y] > dis[x] + e[i].dis )
            {
                dis[y] = dis[x] + e[i].dis;
                if( !vis[y] )
                {
                    q.push( ( node ){dis[y], y} );
                }
            }
        }
    }
}
int main()
{

    while(scanf("%d %d",&n,&m)!=EOF)
    {    
        init();
        int S,T;
        for(int i = 0; i <= n; ++i)dis[i] = inf;//初始化从0开始 
    
    for( register int i = 0; i < m; ++i )
    {
        
        register int u, v, d;
        cin>>u>>v>>d;        // u起点 v终点 d权重 
        add_edge( u, v, d );
        add_edge( v, u, d );
        
    }
    
    cin>>S>>T;  
    
    dijkstra(S);
    
    if(dis[T]!=inf)
    cout<<dis[T]<<endl;
    else
    cout<<-1<<endl;
    }
    return 0;
}