POJ -- 3140

     #include<iostream>
     #include<cstdio>
     #include<cstring>
     #include<string>
     #define MAXN 1000010
     #define LL long long
     const LL INF = 0x7fffffffffffff;
     using namespace std;
     typedef struct{
         int to,next;
     }Node;
     Node edge[*MAXN];
     int vis[MAXN/],head[MAXN/],val[MAXN/];
     LL sum[MAXN/],all_sum,ans;
     LL My_abs(LL tmp){return tmp <  ? -tmp : tmp;}
     void addedge(int u,int v,int k){
         edge[k].to = v;
         edge[k].next = head[u];
         head[u] = k;
     }
     LL dfs_sum(int s){
         vis[s] = ;
         sum[s] = val[s];
         for(int i = head[s];~i;i = edge[i].next){
             int u = edge[i].to;
             if(!vis[u]) sum[s] += dfs_sum(u);
         }
         return sum[s];
     }
     void dfs_minabs(int s){
         vis[s]= ;
         for(int i  = head[s];~i;i = edge[i].next){
             int u = edge[i].to;
             if(!vis[u]){
                 dfs_minabs(u);
                 ans = min(ans,My_abs(all_sum - *sum[u]));
             }
         }
     }
     int main(){
         int n,m,cas = ;
         freopen("in.c","r",stdin);
         while(~scanf("%d%d",&n,&m) && (m+n) ){
             int k = ,tmp,u,v;
             all_sum = ;
             for(int i = ;i <= n;i ++) scanf("%d",&tmp),val[i] = tmp,all_sum += tmp;
             memset(head,-,sizeof(head));
             for(int i = ;i < m;i ++){
                 scanf("%d%d",&u,&v);
                 addedge(u,v,k++);
                 addedge(v,u,k++);
             }
             memset(vis,,sizeof(vis));
             dfs_sum();
             ans = INF;
             memset(vis,,sizeof(vis));
             dfs_minabs();
             if(n == ) ans = val[];
             printf("Case %d: %lld\n",++cas,ans);
         }
         return ;
     }