G - 小希的迷宫

 1 #include<cstdio>
 2 #include<string.h>
 3 using namespace std;
 4 //int rank[100010];
 5 int father[100010];
 6 int max1=0;
 7 int vis[100010];
 8 int find(int x)
 9 {
10     if(x!=father[x])
11         father[x]=find(father[x]);
12     return father[x];
13 }
14 bool Union(int x,int y)
15 {
16     int x1=find(x),y1=find(y);
17     if(x1!=y1)
18     {
19         father[y1]=x1;
20         return true;
21         //rank[x]+=rank[y];
22         //if(max1<rank[x]) max1=rank[x];
23         //return;
24     }
25     return false;
26 }
27 int main()
28 {
29     int a,b;
30     while(scanf("%d %d",&a,&b)!=EOF&&a!=-1&&b!=-1)
31     {
32        for(int i=1;i<=100010;i++)
33            father[i]=i;
34        if(a==0&&b==0){printf("Yes\n");continue;} //注意continue!!!
35        int min=100000000;
36        int max=0;
37        int flag=1;
38        memset(vis,0,sizeof(vis));
39        while(a||b)
40         {
41             if(a>max) max=a;
42             if(b>max) max=b;
43             if(a<min) min=a;
44             if(b<min) min=b;
45             vis[a]=1;
46             vis[b]=1;
47             if(!Union(a,b)) flag=0;
48             scanf("%d %d",&a,&b);
49         }
50         if(flag==0) printf("No\n");
51         else{
52             int ans=0;
53             for(int i=min;i<=max;i++)
54                if(vis[i]&&father[i]==i)
55                    ans++;
56             if(ans==1) printf("Yes\n");
57             else printf("No\n");
58         }
59 
60     }
61     return 0;
62 }

 1 #include<cstdio>
 2 #include<string.h>
 3 using namespace std;
 4 //int rank[100010];
 5 int father[100010];
 6 int rank[100010];
 7 int max1=0;
 8 //int vis[100010];
 9 int find(int x)
10 {
11     if(x!=father[x])
12         father[x]=find(father[x]);
13     return father[x];
14 }
15 bool Union(int x,int y)
16 {
17     int x1=find(x),y1=find(y);
18     if(x1!=y1)
19     {
20         father[y1]=x1;
21 
22         rank[x1]+=rank[y1];//记录深度
23         if(max1<rank[x1]) max1=rank[x1];
24         return true;
25         //rank[x]+=rank[y];
26         //if(max1<rank[x]) max1=rank[x];
27         //return;
28     }
29     return false;
30 }
31 int main()
32 {
33     int a,b;
34     while(scanf("%d %d",&a,&b)!=EOF&&a!=-1&&b!=-1)
35     {
36        for(int i=1;i<=100010;i++)
37        {
38            father[i]=i;rank[i]=1;
39        }
40 
41        if(a==0&&b==0){printf("Yes\n");continue;}
42        int flag=1;
43        //memset(vis,0,sizeof(vis));
44        int ans=0;
45        while(a||b)
46         {
47             ans=ans+1;//这是记录输入的边的条数
48             if(!Union(a,b)) flag=0;
49             scanf("%d %d",&a,&b);
50         }
51        // printf("%d %d\n",ans,max1);
52         if(flag==0) printf("No\n");
53         else if(max1-1==ans) printf("Yes\n");
54         else printf("No\n");
55     }
56     return 0;
57 }