delete pics to save space

history_source/信息学奥赛一本通/3.4.6.4.cpp

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+#include<cstdio>
+int X,Y;
+#define hh(a,b) ((a)*1001+(b))
+int fa[1005000];
+int ff(int n)
+{
+	int a,b;
+	a=n;
+	while(n!=fa[n]) n=fa[n];
+	while(a!=n)
+	{
+		b=fa[a];
+		fa[a]=n;
+		a=b;
+	}
+	return n;
+}
+int main()
+{
+	freopen("grid.in","r",stdin);
+	freopen("grid.out","w",stdout);
+	scanf("%d%d",&Y,&X);
+	int i,j,x1,y1,x2,y2;
+	for(i=1;i<=Y;i++)
+		for(j=1;j<=X;j++)
+			fa[hh(j,i)]=hh(j,i);
+	while(scanf("%d%d%d%d",&y1,&x1,&y2,&x2)==4)
+		if(ff(hh(x1,y1))!=ff(hh(x2,y2)))
+			fa[ff(hh(x2,y2))]=ff(hh(x1,y1));
+	int spend=0;
+	for(i=1;i<Y;i++)
+		for(j=1;j<=X;j++)
+			if(ff(hh(j,i))!=ff(hh(j,i+1)))
+			{
+				spend++;
+				fa[ff(hh(j,i))]=ff(hh(j,i+1));
+			}
+	for(i=1;i<=Y;i++)
+		for(j=1;j<X;j++)
+			if(ff(hh(j,i))!=ff(hh(j+1,i)))
+			{
+				spend+=2;
+				fa[ff(hh(j,i))]=ff(hh(j+1,i));
+			}
+	printf("%d\n",spend);
+	return 0;
+}