传送门：
#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define re register
#define pb push_back
#define mp make_pair
#define fi first
#define se second
const int N=1e6;
const int P=1e9+7;
void read(int &a)
{
a=0;
int d=1;
char ch;
while(ch=getchar(),ch>'9'||ch<'0')
if(ch=='-')
d=-1;
a=ch-'0';
while(ch=getchar(),ch>='0'&&ch<='9')
a=a*10+ch-'0';
a*=d;
}
void write(int x)
{
if(x<0)
putchar(45),x=-x;
if(x>9)
write(x/10);
putchar(x%10+'0');
}
int head[N];
struct note
{
int v,dis,next;
}edge[N];
int num;
void add(int u,int v,int dis)
{
edge[++num].next=head[u];
edge[num].v=v;
edge[num].dis=dis;
head[u]=num;
}
struct node
{
ll cost,now,nowh,pos;
bool operator < (const node & x) const {return x.cost<cost;}
};
priority_queue <node> q;
ll dis[N];
int h[N];
inline void dijstra()
{
memset(dis,0x3f,sizeof(dis));
dis[1]=0;
while(!q.empty())
{
node p=q.top();
q.pop();
int u=p.pos;
if(dis[u]<p.cost)
continue;
for(re int i=head[u];i;i=edge[i].next)
{
int v=edge[i].v;
int w=edge[i].dis;
ll co=min(0ll,p.now-(h[v]-p.nowh));
if(dis[v]>dis[u]+w+co*co)
{
dis[v]=dis[u]+w+co*co;
q.push({dis[v],max(0ll,p.now-(h[v]-p.nowh)),h[v]+co,v});
}
}
}
}
int main()
{
int n,m,k;
read(n);
read(m);
read(k);
for(re int i=1;i<=n;i++)
read(h[i]);
for(re int i=1;i<=m;i++)
{
int u,v,w;
read(u);
read(v);
read(w);
add(u,v,w);
add(v,u,w);
}
q.push({0,k,h[1],1});
dijstra();
cout<<dis[n]<<endl;
return 0;
}