delete pics to save space

history_source/信息学奥赛一本通/3.4.2.1.cpp

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+#include<cstdio>
+#include<cstring>
+#define maxn 105
+bool vis[maxn];
+int n,m,be_smaller[maxn][maxn],num2[maxn],be_bigger[maxn][maxn],num1[maxn],queue[maxn],head,tail;
+//int lit[maxn],big[maxn];
+int f1(int a)
+{
+//	if(lit[a]>-1) return lit[a];
+	head=tail=0;
+	queue[tail++]=a;
+	memset(vis,1,sizeof(vis));
+	static int i;
+	while(head<tail)
+	{
+		for(i=0;i<num1[queue[head]];i++)
+			if(vis[be_bigger[queue[head]][i]])
+			{
+				vis[be_bigger[queue[head]][i]]=0;
+				queue[tail++]=be_bigger[queue[head]][i];
+			}
+		head++;
+	}
+//	lit[a]=tail-1;
+	return tail-1;
+}
+int f2(int a)
+{
+//	if(big[a]>-1) return big[a];
+	head=tail=0;
+	queue[tail++]=a;
+	memset(vis,1,sizeof(vis));
+	static int i;
+	while(head<tail)
+	{
+		for(i=0;i<num2[queue[head]];i++)
+			if(vis[be_smaller[queue[head]][i]])
+			{
+				vis[be_smaller[queue[head]][i]]=0;
+				queue[tail++]=be_smaller[queue[head]][i];
+			}
+		head++;
+	}
+//	big[a]=tail-1;
+	return tail-1;
+}
+//void print()
+//{
+//	for(int i=1;i<=n;i++) printf("lit[%d]=%d ",i,lit[i]);
+//	printf("\n");
+//	for(int i=1;i<=n;i++) printf("big[%d]=%d ",i,big[i]);
+//	printf("\n");
+//}
+int main()
+{
+//	memset(lit,-1,sizeof(lit));
+//	memset(big,-1,sizeof(big));
+	freopen("BEAD.in","r",stdin);
+	freopen("BEAD.out","w",stdout);
+	scanf("%d%d",&n,&m);
+	int i,j,k,a,b,ans=0;
+	for(i=0;i<m;i++)
+	{
+		scanf("%d%d",&a,&b);
+		be_bigger[a][num1[a]++]=b;
+		be_smaller[b][num2[b]++]=a;
+	}
+	for(i=1;i<=n;i++)
+		if(f1(i)>=(n+1)/2||f2(i)>=(n+1)/2) ans++;
+	printf("%d\n",ans);
+//	print();
+	return 0;
+}