1 #include<iostream>
2 #include<cstdio>
3 using namespace std;
4 const int maxn=1e5+7;
5 const int maxm=5e5+7;
6 const int inf=0x7f7f7f7f;
7 int n,m,num;
8 int head[maxn],val[maxn],f[maxn],mi[maxn];
9 int read(){
10 int f=1;int x=0;char s=getchar();
11 while(s<'0'||s>'9') {if(s=='-') f=-1;s=getchar();}
12 while(s>='0'&&s<='9'){x=x*10+s-'0';s=getchar();}
13 x*=f;
14 return x;
15 }
16 struct Edge{
17 int next,to;
18 }edge[maxm];
19 void add(int from,int to){
20 edge[++num].next=head[from];
21 edge[num].to=to;
22 head[from]=num;
23 }
24 void dfs(int x,int pre,int minn){
25 bool flag=1;
26 minn=min(minn,val[x]);
27 if(mi[x]>minn){mi[x]=minn;flag=false;}
28 int maxx=max(f[pre],val[x]-minn);
29 if(f[x]<maxx){f[x]=maxx;flag=false;}
30 if(flag==true) return;
31 for(int i=head[x];i;i=edge[i].next){
32 int v=edge[i].to;
33 dfs(v,x,minn);
34 }
35 }
36 int main(){
37 cin>>n>>m;
38 for(int i=1;i<=n;i++) cin>>val[i];
39 for(int i=1;i<=m;i++){
40 int x,y,z;x=read();y=read();z=read();
41 if(z==1) add(x,y);
42 if(z==2) {add(x,y);add(y,x);}
43 }
44 for(int i=1;i<=n;i++) mi[i]=inf;
45 dfs(1,0,inf);
46 cout<<f[n]<<endl;
47 return 0;
48 }
