1094. The Largest Generation (25)

BFS遍历计算每层孩子数并寻找最大值

最新推荐文章于 2020-10-14 20:46:22 发布

原创最新推荐文章于 2020-10-14 20:46:22 发布 · 391 阅读

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#C++ #PAT #The Largest Generati

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走一遍BFS，计算每一层的孩子数目，同时跟踪最大值

#include <iostream>
#include <cstdio>
#include <vector>
#include <queue>

using namespace std;

vector<vector<int>> tree;

int main(){
	int n,m;
	scanf("%d%d", &n, &m);
	tree.resize(n+1, vector<int>());

	for(int i = 0; i < m; ++i){
		int id, k, child;
		scanf("%d%d", &id, &k);
		for(int j = 0; j < k; ++j){
			scanf("%d", &child);
			tree[id].push_back(child);
		}
	}

	int maxNum = 0, maxLevel = 0;
	vector<int> hist(101, 0);
	queue<pair<int,int>> Q;
	Q.push({1, 1});

	while(!Q.empty()){
		auto p = Q.front(); Q.pop();
		int id = p.first, level = p.second;

		hist[level]++;
		if(hist[level] > maxNum){
			maxNum = hist[level];
			maxLevel = level;
		}

		for(auto& c : tree[id]){
			Q.push({c, level+1});
		}
	}

	printf("%d %d", maxNum, maxLevel);


	return 0;
}