最短路 SPFA

#include<iostream>
#include<cstdio>
#include<cstring>
#include<cstdlib>
#include<cmath>
#include<algorithm>
#define INF 99999999 
using namespace std;
int n,m,k,cnt;
int len[500001],head[500001],jdg[500001],que[500001];
struct uio{
    int to,next,wei;
}edge[500001];
void get(int x,int y,int z)
{
    edge[++cnt].next=head[x];
    edge[cnt].to=y;
    edge[cnt].wei=z;
    head[x]=cnt;
}
int main()
{
    cin>>n>>m>>k;
    memset(head,-1,sizeof(head));
    memset(len,0x3f,sizeof(len));
    for(int i=1;i<=m;i++)
    {
        int a,b,c;
        cin>>a>>b>>c;
        get(a,b,c);
    }
    len[k]=0;
    que[1]=k;
    jdg[k]=1; 
    int s=0,f=1;
    while(s<f)
    {
        s++;
        int num=que[s];
        jdg[num]=0;
        for(int i=head[num];i!=-1;i=edge[i].next)
            if(len[edge[i].to]>len[num]+edge[i].wei)
            {
                len[edge[i].to]=len[num]+edge[i].wei;
                if(jdg[edge[i].to]==0)
                {
                    jdg[edge[i].to]=1;
                    que[++f]=edge[i].to;
                }
            }
    }
    for(int i=1;i<=n;i++)
    {
        if(len[i]==0x3f3f3f3f)
            cout<<"No Ways!!!"<<" ";
        else
            cout<<len[i]<<" ";
    }
    cout<<endl;
    return 0;
}