图的BFS问题

qq_40669215 2020-07-20 05:13:53

#include<cstdio>

#include<queue>

#include<vector>

#include<memory.h>

#define MAX_N 1010

using namespace std;

int n, l;

vector<int> g[MAX_N];

int vertex_level[MAX_N];

bool visited[MAX_N];

int bfs(int node)

{

	memset(vertex_level, 0, MAX_N);

	memset(visited, false, MAX_N);

	queue<int> trav;

	trav.push(node);

	int count = 0;

	visited[node] = true;

	while (!trav.empty() && vertex_level[trav.front()] < l)

	{

		int f = trav.front();

		trav.pop();

		for (int i = 0; i < g[f].size(); ++i)

		{

			if (!visited[g[f][i]])

			{

				visited[g[f][i]] = true;

				vertex_level[g[f][i]] = vertex_level[f] + 1;

				trav.push(g[f][i]);

				++count;

			}

		}

	}

	return count;

}

int main(void)

{

	scanf("%d%d", &n, &l);

	for (int i = 1; i <= n; ++i)

	{

		int s;

		scanf("%d", &s);

		for (int j = 0; j < s; ++j)

		{

			int t;

			scanf("%d", &t);

			g[t].push_back(i);

		}

	}

	int s;

	scanf("%d", &s);

	for (int i = 0; i < s; ++i)

	{

		int t;

		scanf("%d", &t);

		printf("%d\n", bfs(t));

	}

}