add disjoint0

Author: Avantihub

docs/codingprob/FDS/template/disjoint0.cpp

@@ -0,0 +1,36 @@
+// https://vjudge.net/contest/352513#problem/C
+// HDU- 1272
+#include <cstdio>
+#include <algorithm>
+const int N=1e5+10;
+using namespace std;
+int n,f[N],vis[N],flag;
+inline int sf(int x){return x==f[x]?x:f[x]=sf(f[x]);}
+inline void merge(int x,int y)
+{
+	int xx=sf(x),yy=sf(y);
+	if(xx==yy){flag=1;return ;}
+	f[xx]=yy;
+}
+int main()
+{
+	int x,y;
+	while(scanf("%d%d",&x,&y)==2,(~x||~y))
+    {
+		if(!x&&!y){puts("Yes");continue;}
+		for(int i=1;i<N;i++) 
+            f[i]=i,vis[i]=0;
+		flag=0,merge(x,y),vis[x]=vis[y]=1;
+		while(scanf("%d%d",&x,&y)==2,(x||y))
+			merge(x,y),vis[x]=vis[y]=1;
+		if(flag) puts("No");
+        else
+        {
+			int cnt=0;
+			for(int i=1;i<N;i++)
+				if(f[i]==i&&vis[i]) cnt++;
+			if(cnt==1) puts("Yes");
+            else puts("No");	
+		}
+	}
+}