delete pics to save space

7.2054.cpp

@@ -0,0 +1,63 @@
+#include<cstdio>
+#include<cstring>
+#include<vector>
+#include<algorithm>
+using namespace std;
+const int maxn=1005;
+int n,r,v[maxn],vy[maxn],fa[maxn],cnt[maxn],pre[maxn],nxt[maxn];
+void print(int p)
+{
+	int t=p;
+	printf("{%d",p); p=nxt[p];
+	while(p!=t) { printf(",%d",p); p=nxt[p]; }
+	puts("}");
+}
+int main()
+{
+#ifdef local
+	freopen("pro.in","r",stdin);
+#endif
+	while(scanf("%d%d",&n,&r)==2&&!(n==0&&r==0))
+	{
+		memset(cnt,0,sizeof(cnt));
+		memset(fa,0,sizeof(fa));
+		memset(pre,0,sizeof(pre));
+		memset(nxt,0,sizeof(nxt));
+		for(int i=1;i<=n;i++)
+		{
+			scanf("%d",&v[i]);
+			cnt[i]=1; pre[i]=nxt[i]=i;
+		}
+		memcpy(vy,v,sizeof(vy));
+		for(int i=0;i<n-1;i++)
+		{
+			int x,y; scanf("%d%d",&x,&y);
+			fa[y]=x;
+		}
+		for(int i=0;i<n-1;i++)
+		{
+			int p=0;
+			for(int j=1;j<=n;j++) if(j!=r&&cnt[j])
+			{
+				if(!p) p=j;
+				else if(v[p]*cnt[j]<v[j]*cnt[p]) p=j;
+			}
+//			printf("pose %d\n",p);
+			int f=fa[p];
+			while(!cnt[f]) fa[p]=f=fa[f];
+			int tmp=pre[p];
+			pre[p]=pre[f];
+			nxt[tmp]=f;
+			pre[f]=tmp;
+			nxt[pre[p]]=p;
+			v[f]+=v[p];
+			cnt[f]+=cnt[p];
+			cnt[p]=0;
+		}
+		int res=0;
+		for(int i=1,p=r;i<=n;i++,p=nxt[p]) res+=i*vy[p];
+//		print(r);
+		printf("%d\n",res);
+	}
+	return 0;
+}