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Time Limit: 2000/1000 MS (Java/Others) Memory Limit: 32768/32768 K (Java/Others)Total Submission(s): 1781 Accepted Submission(s): 1065
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
Author
ZSTU
Source
题意:给你公司几个人的关系,表示a是b的直接上司,问你手下管理着k个人的人有多少个
这题想到并查集还是比较自然的。。。把并查集模版的状态压缩去掉,新开一个数组表示每个人手下有多少人。然后每次回溯找父节点的时候对相应的管理人数++
代码:
#include <iostream>
#include <cstring>
#include <cstdio>
#include <algorithm>
#include <vector>
#include <cmath>
#include <map>
#include <set>
using namespace std;
const int maxn = 150;
int save[maxn];
int manager[maxn];
int pre[maxn];
int find(int x){
int r=x;
while(pre[r]!=r){
manager[pre[r]]++;
r=pre[r];
//cout<<"aaa";
}
/*if(pre[x]!=r){
pre[x]=r;
}*/
return r;
}
void join(int a,int b){
pre[b]=a;
}
int main(){
int n,k;
while(~scanf("%d%d",&n,&k)){
int a,b,i;
memset(manager, 0, sizeof(manager));
for(i=1;i<=n;i++){
pre[i]=i;
}
for(i=1;i<=n-1;i++){
scanf("%d%d",&a,&b);
join(a, b);
}
for(i=1;i<=n;i++){
find(i);
}
int ans=0;
for(i=1;i<=n;i++){
if(manager[i]==k){
ans++;
}
}
printf("%d\n",ans);
}
}