spfa模板

spfa模板

【代码】

#include<algorithm>
#include<iostream>
#include<cstring>
#include<cstdio>
#include<cmath>
#include<queue>
#include<set>
using namespace std;
#define f(i,n) for(int i=1;i<=(n);i++)
#define ll long long
#define INF 1<<30
#define N 100010
#define M 200010
int n,m;
int read()
{
 	int x=0,f=1;char c=getchar();
 	while(!isdigit(c)){if(c=='-')f=-1;c=getchar();}
 	while( isdigit(c)){x=x*10+c-'0';c=getchar();}
 	return x*f;
}
struct xj
{
	int y;
	int next;
	int v;
}map[2*M];
int cnt;
int head[N];
void add_edge(int u,int v,int z)
{
	map[++cnt].y=v;
	map[cnt].v=z;
	map[cnt].next=head[u];
	head[u]=cnt;
}
queue<int> q;
int vis[N],dis[N];
void spfa()
{
	memset(vis,0,sizeof(vis));
	f(i,n)dis[i]=INF;
	while(q.size())q.pop();
	dis[1]=0;
	vis[1]=1;
	q.push(1);
	while(q.size())
	{
		int x=q.front();
		q.pop();
		for(int i=head[x];i;i=map[i].next)
		{
			if(dis[map[i].y]>dis[x]+map[i].v)
			{
				dis[map[i].y]=dis[x]+map[i].v;
				if(!vis[map[i].y])
				{
					q.push(map[i].y);
					vis[map[i].y]=1;
				}
			}
		}
		vis[x]=0;
	}
}
int main()
{
	n=read();
	m=read();
	int u,v,z;
	f(i,m)
	{
		u=read();
		v=read();
		z=read();
	    add_edge(u,v,z);
	    add_edge(v,u,z);
	} 
	spfa(); 
	f(i,n)printf("%d ",dis[i]);
}