A1094 The Largest Generation [dfs/bfs]

这里是按层求最大节点个数及所在的层数，所以要每条路走一遍记录一下。

#include<iostream>
#include<vector>
#include<queue>
#include<stack>
#include<string>
#include<math.h>
#include<algorithm>
using namespace std;
const int maxn = 110;
vector<int>node[maxn];
int hashtable[maxn];
int maxLevel = -1;
void dfs(int index, int level)
{
	hashtable[level]++;
	if (level > maxLevel)
		maxLevel = level;
    if (node[index].size() == 0)
		return;
	for (int i = 0; i < node[index].size(); i++)
	{
		dfs(node[index][i], level + 1);
	}
}
int main()
{
	int n, m, parent, k, child;
	cin >> n >> m;
	for (int i = 0; i < m; i++)
	{
		cin >> parent >> k;
		for (int j = 0; j < k; j++)
		{
			cin >> child;
			node[parent].push_back(child);
		}
	}
	dfs(1, 1);
	int maxlevel = 0, maxcount = 0;
	for (int i = 1; i <= maxLevel; i++)
	{
		if (hashtable[i] > maxcount)
		{
			maxcount = hashtable[i];
			maxlevel = i;
		}
	}
	cout << maxcount << " " << maxlevel << endl;
}

#include<iostream>
#include<vector>
#include<queue>
#include<stack>
#include<string>
#include<math.h>
#include<algorithm>
using namespace std;
const int maxn = 110;
vector<int>node[maxn];
int hashtable[maxn];
int level[maxn];
int maxLevel = -1;
void bfs(int index)
{
	queue<int>q;
	q.push(index);
	level[index] = 1;
	while (!q.empty())
	{
		int temp = q.front();
		q.pop();
		hashtable[level[temp]]++;
		for (int i = 0; i < node[temp].size(); i++)
		{
			q.push(node[temp][i]);
			level[node[temp][i]] = level[temp] + 1;
		}
	}
}
int main()
{
	int n, m, parent, k, child;
	cin >> n >> m;
	for (int i = 0; i < m; i++)
	{
		cin >> parent >> k;
		for (int j = 0; j < k; j++)
		{
			cin >> child;
			node[parent].push_back(child);
		}
	}
	bfs(1);
	int maxlevel = 0, maxcount = 0;
	for (int i = 1; i <= maxn; i++)
	{
		if (hashtable[i] > maxcount)
		{
			maxcount = hashtable[i];
			maxlevel = i;
		}
	}
	cout << maxcount << " " << maxlevel << endl;
}