8.Is Graph Bipartite?

Given an undirected graph, return true if and only if it is bipartite.

class Solution
{
public:
    bool checkBipartite(vector<vector<int>> &graph, int node, vector<bool> &vs, vector<int> &color)
    {
        queue<int> q;
        q.push(node);
        vs[node] = 1;
        color[node] = 1;

        while (!q.empty())
        {
            int x = q.front();
            q.pop();
            for (int i = 0; i < graph[x].size(); i++)
            {
                if (vs[graph[x][i]] == 0)
                {
                    vs[graph[x][i]] = 1;
                    q.push(graph[x][i]);
                    color[graph[x][i]] = 1 - color[x];
                }
                else
                {
                    if (color[graph[x][i]] == color[x])
                    {
                        return false;
                    }
                }
            }
        }

        return true;
    }
    
    bool isBipartite(vector<vector<int>> &graph)
    {
        int n = graph.size();
        vector<bool> vs(n);
        vector<int> color(n, -1);

        for (int i = 0; i < n; i++)
        {
            if (vs[i] == 0)
            {
                if (!checkBipartite(graph, i, vs, color))
                {
                    return false;
                }
            }
        }
        return true;
    }
};