POJ2387 最短路入门题 [spfa,dijstra+heap]

#include<iostream>
#include<vector>
#include<string>
#include<queue>
#include<algorithm>
#define llong long long
#define Abs(a) ((a)>0?(a):-(a))
#define Mod(a,b) (((a)-1+(b))%(b)+1)
using namespace std;
const int N=1005;
const int M=2005;
const int inf=(1<<29);
int n,m;
int d
;
struct
{
int v,w,next;
}edge[2*M];
int edgehead
;
int k;
bool vis
;
void addedge(int u,int v,int w)
{
edge[k].next=edgehead[u];
edge[k].w=w;
edge[k].v=v;
edgehead[u]=k++;
}
int spfa(int s)
{
queue<int> que;
for(int i=1;i<=n;i++)
d[i]=inf;
d[s]=0;
memset(vis,0,sizeof(vis));
que.push(s);
while(!que.empty())
{
int u=que.front();
que.pop();
vis[u]=false;
for(int i=edgehead[u];i;i=edge[i].next)
{
int v=edge[i].v;
int w=edge[i].w;
if(d[v]>d[u]+w)
{
d[v]=d[u]+w;
if(!vis[v])
{
que.push(v);
vis[v]=true;
}
}
}
}
return d
;
}
int main()
{
scanf("%d%d",&m,&n);
int u,v,w;
k=1;
for(int i=1;i<=m;i++)
{
scanf("%d%d%d",&u,&v,&w);
addedge(u,v,w);
addedge(v,u,w);
}
printf("%d\n",spfa(1));
return 0;
}

#include<iostream>
#include<vector>
#include<string>
#include<queue>
#include<algorithm>
#define llong long long
#define Abs(a) ((a)>0?(a):-(a))
#define Mod(a,b) (((a)-1+(b))%(b)+1)
using namespace std;
const int N=1005;
const int M=2005;
const int inf=(1<<29);
int n,m;
int d
;
struct
{
int v,w,next;
}edge[2*M];
int edgehead
;
int k;
bool vis
;
void addedge(int u,int v,int w)
{
edge[k].next=edgehead[u];
edge[k].w=w;
edge[k].v=v;
edgehead[u]=k++;
}
struct cmp
{
bool operator ()(const int a,const int b)
{
return d[a]>d[b];
}
};
int dijstra(int s)
{
priority_queue<int,vector<int>,cmp> que;
for(int i=1;i<=n;i++)
d[i]=inf;
d[s]=0;
memset(vis,0,sizeof(vis));
que.push(1);
while(!que.empty())
{
int u=que.top();
que.pop();
if(vis[u])//这行代码去除之后时间居然变成0ms,有点郁闷。
continue;
vis[u]=true;
for(int i=edgehead[u];i;i=edge[i].next)
{
int v=edge[i].v;
int w=edge[i].w;
if(!vis[v]&&d[v]>d[u]+w)
{
d[v]=d[u]+w;
que.push(v);
}
}
}
return d
;
}
int main()
{
scanf("%d%d",&m,&n);
int u,v,w;
k=1;
for(int i=1;i<=m;i++)
{
scanf("%d%d%d",&u,&v,&w);
addedge(u,v,w);
addedge(v,u,w);
}
printf("%d\n",dijstra(1));
return 0;
}