【PAT甲級】1004 Counting Leaves (30 分)
A family hierarchy is usually presented by a pedigree tree. Your job is to count those family members who have no child.
Input Specification:
Each input file contains one test case. Each case starts with a line containing 0<N<100, the number of nodes in a tree, and M (<N), the number of non-leaf nodes. Then M lines follow, each in the format:
ID K ID[1] ID[2] ... ID[K]
where ID
is a two-digit number representing a given non-leaf node, K
is the number of its children, followed by a sequence of two-digit ID
's of its children. For the sake of simplicity, let us fix the root ID to be 01
.
The input ends with N being 0. That case must NOT be processed.
Output Specification:
For each test case, you are supposed to count those family members who have no child for every seniority level starting from the root. The numbers must be printed in a line, separated by a space, and there must be no extra space at the end of each line.
The sample case represents a tree with only 2 nodes, where 01
02
is its only child. Hence on the root 01
level, there is 0
leaf node; and on the next level, there is 1
leaf node. Then we should output 0 1
in a line.
Sample Input:
2 1
01 1 02
Sample Output:
0 1
【翻譯】:輸入N,M,分別代表樹的節點數和非葉子節點總數,接下來的M行輸入非葉子節點ID(兩位數),k,孩子數,ID[1]......ID[k],孩子節點的ID,輸入以0結尾,輸出從根節點開始每一層孩子節點數,資料間有空格,行尾沒有空格。
又是參考柳神的,確實很easy,就是用dfs,首先用vector構建數,然後用深搜搜每一層就好了。
#include <iostream>
#include <algorithm>
#include <vector>
#define MAX 1000
using namespace std;
int ans[MAX];
int maxdep = -1;
vector<int> v[MAX];
void dfs(int index,int depth){
if(v[index].size() == 0){
ans[depth]++;
maxdep = max(depth, maxdep);
return;
}
for(int i = 0; i < v[index].size(); i++){
dfs(v[index][i], depth + 1);
}
}
int main(){
int n,m,k,c,id;//n是樹的節點數,m樹中無葉子節點的節點數
cin>>n>>m;
for(int i = 0; i < m; i++){
cin>>id>>k;
for(int j = 0; j < k; j++){
cin>>c;
v[id].push_back(c);
}
}
dfs(1,0);
cout<<ans[0];
for(int i = 1; i <= maxdep; i++){
cout<<" "<<ans[i];
}
return 0;
}