NBUT 1218 You are my brother 2010辽宁省赛

Time limit 1000 ms

Memory limit 131072 kB

Little A gets to know a new friend, Little B, recently. One day, they realize that they are family 500 years ago. Now, Little A wants to know whether Little B is his elder, younger or brother.

Input

There are multiple test cases.
For each test case, the first line has a single integer, n (n<=1000). The next n lines have two integers a and b (1<=a,b<=2000) each, indicating b is the father of a. One person has exactly one father, of course. Little A is numbered 1 and Little B is numbered 2.
Proceed to the end of file.

Output

For each test case, if Little B is Little A’s younger, print “You are my younger”. Otherwise, if Little B is Little A’s elder, print “You are my elder”. Otherwise, print “You are my brother”. The output for each test case occupied exactly one line.

Sample Input

Sample Output

You are my elder
You are my brother


签到题，树的基本概念，代码如下：

 1 #include <iostream>
 2 #include<cstdio>
 3 #include<cstring>
 4 #include<algorithm>
 5 #include<stack>
 6 #include<map>
 7 #include<set>
 8 #include<queue>
 9 #include<cmath>
10 #include<string>
11 using namespace std;
12 int n,t;
13 int fa[2005];
14 int x,y;
15 int main()
16 {
17     while(~scanf("%d",&n))
18     {
19         memset(fa,0,sizeof(fa));
20         for(int i=1;i<=n;i++)
21         {
22             scanf("%d%d",&x,&y);
23             fa[x]=y;
24         }
25         int la=0,lb=0;
26         int k=1;
27         while(fa[k]!=k)
28         {
29             la++;
30             k=fa[k];
31         }
32         k=2;
33         while(fa[k]!=k)
34         {
35             lb++;
36             k=fa[k];
37         }
38         if (la==lb) printf("You are my brother
");
39         else
40         if (lb>la) printf("You are my younger
");
41         else
42         if (lb<la) printf("You are my elder
");
43     }
44     return 0;
45 }