链式前向星模板

#include<bits/stdc++.h>
#define ll long long 
#define scan(i) scanf("%d",&i)
#define scand(i) scanf("%lf",&i)
#define scanl(i) scanf("%lld",&i)
#define f(i,a,b) for(int i=a;i<=b;i++) 
#define pb(i) push_back(i)
#define ppb pop_back()
#define pf printf
#define dbg(args...) cout<<#args<<" : "<<args<<endl;
#define input freopen("in.txt","r",stdin)
#define output freopen("out.txt","w",stdout)
#define io ios::sync_with_stdio(0)
#define fin freopen("in.txt","r",stdin) 
using namespace std;
const int N=10005;
int head[N],cnt;
void init(){
    memset(head,-1,sizeof(head));
    cnt=0;
}
struct edge{
    int to,nxt,w;
}e[N<<1];
void add(int u, int v, int w){
    e[cnt].to=v;
    e[cnt].w=w;
    e[cnt].nxt=head[u];
    head[u]=cnt++;
}
//for(int j=head[u]; j!=-1; j=e[j].nxt){
//    v=e[j].to;//u、v间连了边 
//    w=e[j].w;//边权为w 
//}
int u,v,w;