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, the number of nodes in a tree, and M (<), 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 is the root and 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

题目分析 ：第一行给了你2个数字，一个代表的是总节点数，一个代表的是叶子节点数 之后的几行 父亲节点与子节点，要求算出每一层叶子节点的数量
参考了别人的答案https://blog.csdn.net/qq_37613112/article/details/90577948
就是先将所有节点都先录入，然后对所有节点遍历，当它父亲节点的层数确定好后，它自己的层数也就能确定了

#include<iostream>
#include<string>
#include<stdlib.h>
#include<vector>
#define MaxNum 101
using namespace std;
typedef struct Node
{
    int child = 0;
    int level = -1;
    int father;
}Tree[MaxNum];

int main()
{
    Tree tree;
    int n, m;
    cin >> n>> m;
    for (int k = 0; k < m; k++)
    {
        int id,c,idj;
        cin >> id >> c;
        for (int j = 0; j < c; j++)
        {
            cin >> idj;
            tree[id].child++;
            tree[idj].father = id;
        }
    }
    tree[1].father = 1;
    tree[1].level = 0;
    if (n == 1)
    {
        cout << "1" << endl;
        return 0;
    }
    int flag = 1;
    while (flag)
    {
        flag = 0;
        for (int i = 1; i <=n; i++)
        {
            if (tree[tree[i].father].level != -1 && tree[i].level == -1)tree[i].level = tree[tree[i].father].level + 1;
            else if (tree[tree[i].father].level == -1)
                flag = 1;
        }
    }
    int Level[MaxNum] = { 0 };
    int MaxLevel = -1;
    for (int i =1; i <=n; i++)
    {
        if (tree[i].child== 0)Level[tree[i].level]++;
        MaxLevel = MaxLevel > tree[i].level ? MaxLevel : tree[i].level;
    }
    cout << Level[0];
    for (int i = 1; i <= MaxLevel; i++)
        cout << " " << Level[i];
    return 0;
}