delete pics to save space

2.1572.cpp

@@ -0,0 +1,56 @@
+#include<cstdio>
+#include<cstring> 
+const int N=52;
+int g[N][N];
+int c[N];
+inline int id(char a1, char a2)
+{
+	return ((a1-'A')<<1)+(a2=='+'?0:1);
+}
+inline void connect(char a1,char a2,char b1,char b2)
+{
+	if(a1=='0'||b1=='0') return;
+	int u=id(a1,a2)^1,v=id(b1,b2);
+	g[u][v] = 1;
+}
+bool toposort(int u)
+{
+	c[u]=-1;
+	for(int v=0;v<N;v++)
+	if(g[u][v])
+	{
+		if(c[v]<0) return true;
+		else if(!c[v]&&toposort(v)) return true;
+	}
+	c[u]=1;
+	return false;
+}
+inline bool cycle()
+{
+	memset(c,0,sizeof(c));
+	for (int i=0;i<N;i++)
+		if(!c[i]&&toposort(i)) return true;
+	return false;
+}
+int main()
+{
+#ifdef local
+	freopen("pro.in","r",stdin);
+#endif 
+	int n;
+	while(scanf("%d",&n)==1&&n)
+	{
+		memset(g,0,sizeof(g));
+		while(n--)
+		{
+			char s[10];
+			scanf("%s",s);
+			for(int i=0;i<4;i++)
+				for(int j=0;j<4;j++)
+					if(i!=j)
+						connect(s[i<<1],s[(i<<1)+1],s[j<<1],s[(j<<1)+1]);
+		}
+		printf("%s\n",cycle()?"unbounded":"bounded");
+	}
+	return 0;
+}