1 #include <cstdio> 2 #include <cstring> 3 #include <algorithm> 4 #include <queue> 5 #define inc(i,j,k) for(int i=j;i<=k;i++) 6 #define maxn 100010 7 #define ll long long 8 using namespace std; 9 10 inline int read(){11     char ch=getchar(); int f=1,x=0;12     while(ch<‘0‘||ch>‘9‘){if(ch==‘-‘)f=-1; ch=getchar();}13     while(ch>=‘0‘&&ch<=‘9‘)x=x*10+ch-‘0‘,ch=getchar();14     return f*x;15 }16 struct e{int t; ll w; int n;}es[maxn*2]; int g[maxn],ess;17 void pe(int f,int t,ll w){es[++ess]=(e){t,w,g[f]}; g[f]=ess;}18 ll ds[maxn],sz[maxn],fads[maxn],dep[maxn],c[maxn],sum; int n,ans,fa[maxn];19 void dfs1(int x){20     sz[x]=c[x]; ds[x]=0;21     for(int i=g[x];i;i=es[i].n)if(es[i].t!=fa[x]){22         fa[es[i].t]=x; dep[es[i].t]=dep[x]+es[i].w; dfs1(es[i].t);23         sz[x]+=sz[es[i].t]; ds[x]+=ds[es[i].t]+sz[es[i].t]*es[i].w;24     }25 }26 void dfs2(int x,ll a,ll b){27     fads[x]=a+b*(sum-sz[x]); ll sm=fads[x];28     for(int i=g[x];i;i=es[i].n)if(es[i].t!=fa[x])sm+=ds[es[i].t]+es[i].w*sz[es[i].t];29     for(int i=g[x];i;i=es[i].n)if(es[i].t!=fa[x])dfs2(es[i].t,sm-(ds[es[i].t]+es[i].w*sz[es[i].t]),es[i].w);30 }31 int main(){32     n=read(); inc(i,1,n)c[i]=read(),sum+=c[i];33     inc(i,1,n-1){int x=read(),y=read(),z=read(); pe(x,y,z); pe(y,x,z);} dfs1(1); dfs2(1,0,0); 34     ans=1; inc(i,2,n)if(fads[i]+ds[i]<fads[ans]+ds[ans])ans=i; printf("%lld",fads[ans]+ds[ans]); return 0;35 }