Party at Hali-Bula
I'm going to have a party at my villa at Hali-Bula to celebrate my retirement from BCM. I wish I could invite all my co-workers, but imagine how an employee can enjoy a party when he finds his boss among the guests! So, I decide not to invite both an employee
and his/her boss. The organizational hierarchy at BCM is such that nobody has more than one boss, and there is one and only one employee with no boss at all (the Big Boss)! Can I ask you to please write a program to determine the maximum number of guests so
that no employee is invited when his/her boss is invited too? I've attached the list of employees and the organizational hierarchy of BCM.
Best,
--Brian Bennett
P.S. I would be very grateful if your program can indicate whether the list of people is uniquely determined if I choose to invite the maximum number of guests with that condition.
employee together with the name of his/her boss. All names are strings of at least one and at most 100 letters and are separated by blanks. The last line of each test case contains a single 0.
6 Jason Jack Jason Joe Jack Jill Jason John Jack Jim Jill 2 Ming Cho Ming 0
4 Yes 1 No
#include<cstdio>
#include<cstring>
#include<string>
#include<map>
#include<vector>
using namespace std;
#define N 210
map<string,int> st;
int n,num,dp[N][2];
//dp[i][0]表示不选择i点时，i点及其子树能选出的最多人数
//dp[i][1]表示选择i点时，i点及其子树能选出的最多人数
vector<int> child[N];
bool flag[N][2];
int getNum(string &a)
{
if(st.count(a))
return st.find(a)->second;
else
st.insert(make_pair(a,num++));
return num-1;
}
void dfs(int x)
{
for(int i=0;i<child[x].size();++i)
{
int y=child[x][i];
dfs(y);
dp[x][1]+=dp[y][0];
dp[x][0]+=max(dp[y][0],dp[y][1]);
if((dp[y][0]>dp[y][1]&&!flag[y][0])||(dp[y][0]<dp[y][1]&&!flag[y][1])||dp[y][0]==dp[y][1])//判断答案是否唯一
flag[x][0]=false;
if(!flag[y][0])
flag[x][1]=false;
}
dp[x][1]++;
}
int main()
{
char stra[200],strb[200];
string sa,sb;
int a,b,s;
for(;scanf("%d",&n)&&n;)
{
num=1;
for(int i=0;i<=n;++i)
child[i].clear();
memset(dp,0,sizeof(dp));
memset(flag,true,sizeof(flag));
st.clear();
scanf("%s",stra);
sa=string(stra);
s=getNum(sa);
for(int i=1;i<n;++i)
{
scanf("%s %s",stra,strb);
sa=string(stra);
sb=string(strb);
child[getNum(sb)].push_back(getNum(sa));
}
dfs(s);
printf("%d ",max(dp[s][0],dp[s][1]));
if(dp[s][0]>dp[s][1]&&flag[s][0])
puts("Yes");
else if(dp[s][1]>dp[s][0]&&flag[s][1])
puts("Yes");
else puts("No");
}
return 0;
}