delete pics to save space

1.2279.cpp

@@ -0,0 +1,34 @@
+#include<cstdio>
+#include<algorithm>
+#include<vector>
+using namespace std;
+const int maxn=1005;
+int n,f[maxn],d[maxn],p[maxn],mark[maxn],res,ok[maxn],mark2[maxn];
+inline bool cmp(int a,int b) { return d[a]>d[b]; }
+int main()
+{
+#ifdef local
+	freopen("pro.in","r",stdin);
+#endif
+	scanf("%d",&n);
+	f[1]=1; d[1]=1; p[1]=1;
+	for(int i=2;i<=n;i++)
+	{
+		scanf("%d",&f[i]);
+		d[i]=d[f[i]]+1;
+		p[i]=i;
+	}
+	sort(p+1,p+1+n,cmp);
+	for(int i=1;i<=n;i++)
+	{
+		int u=p[i];
+		if(mark[u]||mark[f[u]]||mark[f[f[u]]]||ok[u]||mark2[f[u]]) { ok[u]=true; continue; }
+		int v=f[f[u]];
+		mark[v]=true;
+		ok[u]=ok[f[u]]=ok[v]=ok[f[v]]=ok[f[f[v]]]=true;
+		mark2[f[v]]=true;
+		res++;
+	}
+	printf("%d\n",res);
+	return 0;
+}