delete pics to save space

1.3698.cpp

@@ -0,0 +1,47 @@
+#include<cstdio>
+#include<vector>
+#include<algorithm>
+using namespace std;
+const int maxn=105;
+int n,V;
+vector<int> G[maxn];
+int dp[maxn][maxn],vis[maxn][maxn],size[maxn];
+void dfs(int u,int fa)
+{
+	size[u]=1;
+	for(int i=0;i<G[u].size();i++)
+	{
+		int v=G[u][i];
+		if(v==fa) continue;
+		dfs(v,u); size[u]+=size[v];
+	}
+}
+int f(int u,int step,int fa)
+{
+	int &res=dp[u][step];
+	if(vis[u][step]) return res;
+	vis[u][step]=true;
+	res=min(size[u],1+step/2);
+	for(int i=0;i<G[u].size();i++)
+	{
+		int v=G[u][i];
+		if(v==fa) continue;
+		for(int j=1;j<=step;j++) res=max(res,min(size[u]-size[v],1+(step-j)/2)+f(v,j-1,u));
+	}
+	return res;
+}
+int main()
+{
+#ifdef local
+	freopen("pro.in","r",stdin);
+#endif
+	scanf("%d%d",&n,&V);
+	for(int i=0;i<n-1;i++)
+	{
+		int a,b; scanf("%d%d",&a,&b);
+		G[a].push_back(b); G[b].push_back(a);
+	}
+	dfs(0,-1);
+	printf("%d\n",f(0,V,-1));
+	return 0;
+}