delete pics to save space

7.2912.cpp

@@ -0,0 +1,80 @@
+#include<cstdio>
+#include<cstring>
+#include<algorithm>
+using namespace std;
+const int maxn=505;
+const int maxm=2005;
+int n,m,x[maxm],d[maxm],y[maxm],fa[maxn*3];
+inline int ff(int u)
+{
+	int a=u,b;
+	while(u!=fa[u]) u=fa[u];
+	while(a!=u)
+	{
+		b=fa[a];
+		fa[a]=u;
+		a=b;
+	}
+	return u;
+}
+inline void merge(int x,int y)
+{
+	x=ff(x); y=ff(y);
+	fa[x]=y;
+}
+int check(int id)
+{
+	for(int i=1;i<=n*3;i++) fa[i]=i;
+	for(int i=1;i<=m;i++)
+	{
+		if(x[i]==id||y[i]==id) continue;
+		int Xself=x[i]*3,Xeat=x[i]*3-1,Xenemy=x[i]*3-2;
+		int Yself=y[i]*3,Yeat=y[i]*3-1,Yenemy=y[i]*3-2;
+		if(d[i]==0)
+		{
+			if(ff(Xeat)==ff(Yself)) return i;
+			if(ff(Xself)==ff(Yeat)) return i;
+			merge(Xeat,Yeat);
+			merge(Xself,Yself);
+			merge(Xenemy,Yenemy);
+		}
+		else
+		{
+			if(ff(Xself)==ff(Yself)) return i;
+			if(ff(Xself)==ff(Yeat)) return i;
+			merge(Xeat,Yself);
+			merge(Xself,Yenemy);
+			merge(Xenemy,Yeat);
+		}
+	}
+	return 0;
+}
+int main()
+{
+#ifdef local
+	freopen("pro.in","r",stdin);
+#endif
+	while(scanf("%d%d",&n,&m)==2)
+	{
+		for(int i=1;i<=m;i++)
+		{
+			char op; scanf("%d%c%d",&x[i],&op,&y[i]);
+			x[i]++; y[i]++;
+			d[i]=(op=='>'?1:(op=='='?0:-1));
+			if(d[i]==-1) d[i]=1,swap(x[i],y[i]);
+		}
+		// for(int i=1;i<=m;i++) printf("%d %d %d\n",x[i],d[i],y[i]);
+		// puts("");
+		int rd=0,tot=0,id=0;
+		for(int i=1;i<=n;i++)
+		{
+			int v=check(i);
+			rd=max(rd,v);
+			if(v==0) tot++,id=i;
+		}
+		if(tot==0) puts("Impossible");
+		else if(tot>1) puts("Can not determine");
+		else printf("Player %d can be determined to be the judge after %d lines\n",id-1,rd);
+	}
+	return 0;
+}