1004 Counting Leaves

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

import java.util.* ;

public class Main{

    static class Node{

        int id;

        Queue<Node> children;

        Node(int id){

            this.id=id;

        }

    }

    static HashMap<Integer,Node> tree;

    static int N;//树的节点个数

    static int M;//有孩子的节点数

    public static void main(String[] args) {

        Scanner sc = new Scanner(System.in);

        N = sc.nextInt();

        M = sc.nextInt();

        tree = new HashMap<>();

        for(int i=;i<M;i++){

            int id=sc.nextInt();

            int K = sc.nextInt();

            Node node = new Node(id);

            Queue<Node> children = new LinkedList<>();

            for(int j=;j<K;j++){

                Node no = new Node(sc.nextInt());

                children.offer(no);

            }

            node.children=children;

            tree.put(id,node);

        }

        Queue<Node> que =new LinkedList<>();

        que.add(tree.get());

        BFS(que);

    }

    public static void BFS(Queue<Node> que){

        int len = ;

        Queue<Node> NextQue = new LinkedList<>();

        while(que.size()!=){

            Node node = que.poll();

            if(tree.size()==||!tree.containsKey(node.id)){

                len++;

            }else{

                NextQue.addAll(tree.get(node.id).children);

            }

        }

        if(NextQue.size()==){

            System.out.print(len);

        }

        else {

            System.out.print(len+" ");

            BFS(NextQue);

        }

    }

}

思路为BFS。

HashMap建树。

巴特西

1004 Counting Leaves

Input Specification:

Output Specification:

Sample Input:

Sample Output:

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