Work
Time Limit: 2000/1000 MS (Java/Others) Memory Limit: 32768/32768 K (Java/Others)Total Submission(s): 557 Accepted Submission(s): 376
Problem Description

It’s an interesting experience to move from ICPC to work, end my college life and start a brand new journey in company.
As is known to all, every stuff in a company has a title, everyone except the boss has a direct leader, and all the relationship forms a tree. If A’s title is higher than B(A is the direct or indirect leader of B), we call it A manages B.
Now, give you the relation of a company, can you calculate how many people manage k people.
Input
There are multiple test cases.
Each test case begins with two integers n and k, n indicates the number of stuff of the company.
Each of the following n-1 lines has two integers A and B, means A is the direct leader of B.
1 <= n <= 100 , 0 <= k < n
1 <= A, B <= n
Each test case begins with two integers n and k, n indicates the number of stuff of the company.
Each of the following n-1 lines has two integers A and B, means A is the direct leader of B.
1 <= n <= 100 , 0 <= k < n
1 <= A, B <= n
Output
For each test case, output the answer as described above.
Sample Input
7 2 1 2 1 3 2 4 2 5 3 6 3 7
Sample Output
2
Source
求子树中结点树恰好为k(不包括子树的根)的结点个数
建图,直接深搜即可
#include<iostream>
#include<cstdio>
#include<cstring>
#include<vector>
using namespace std;
vector<int>haha[200];
int check[200];
int num[200];
int dfs(int u){
if(check[u]) return num[u]+1;
check[u] = 1;
for(int i = 0; i < haha[u].size();i++)
num[u] += dfs(haha[u][i]);
return num[u]+1;
}
int main(){
int n,k;
while(scanf("%d%d",&n,&k)!=EOF){
for(int i = 0;i <= n; i++)
haha[i].clear();
int u,v;
for(int i =1;i < n; i++){
scanf("%d%d",&u,&v);
haha[u].push_back(v);
}
memset(check,0,sizeof(check));
memset(num,0,sizeof(num));
int ans = 0;
for(int i = 1;i <= n; i++){
if(check[i]) continue;
dfs(i);
}
for(int i =1;i <= n; i++)
if(num[i]==k) ans++;
cout<<ans<<endl;
}
return 0;
}