1094 The Largest Generation (25point(s)) Easy only once

Posted 2021-03-10 songlinxuan

基本思想：

层序遍历问题；

 

关键点：

无；

 

#include<iostream>
#include<stdlib.h>
#include<stdio.h>
#include<vector> 
#include<string>
#include<math.h>
#include<algorithm>
#include<cstring>
#include<map>
#include<queue>
using namespace std;

int n, m;
int cnt=0;
int f_layer=0;
struct node {
	vector<int>child;
	int layer;
};

vector<node>tree;

void layer_init() {
	if (tree.size() == 0)
		return;
	tree[1].layer = 1;
	queue<int>q;
	q.push(1);
	while (!q.empty()){
		int index = q.front();
		q.pop();
		for (int i = 0; i < tree[index].child.size(); i++) {
			tree[tree[index].child[i]].layer = tree[index].layer + 1;
			q.push(tree[index].child[i]);
		}
	}
}

void layer_find() {
	if (tree.size() == 0)
		return;
	queue<int>q;
	q.push(1);
	int l = 0;
	int c = 0;
	while (!q.empty()) {
		l++;
		c = q.size();
		for (int i = 0; i < c; i++) {
			int index = q.front();
			q.pop();
			for (int j = 0; j < tree[index].child.size(); j++) {
				q.push(tree[index].child[j]);
			}
		}
		if (cnt < c) {
			cnt = c;
			f_layer = l;
		}
	}
}

int main() {
	cin >> n >> m;
	int a, b,c;
	tree.resize(n+1);
	for (int i = 0; i < m; i++) {
		cin >> a >> b;
		for (int j = 0; j < b; j++) {
			cin >> c;
			tree[a].child.push_back(c);
		}
	}
	layer_find();
	cout << cnt << " " << f_layer;
	return 0;
}