LeetCode:785.判断二分图

class Solution {
     
    private boolean[] visited;
	private int []colors;
	private int [][]graph;
    public boolean isBipartite(int[][] graph) {
     

		this.graph=graph;
		int V =graph.length;
		visited=new boolean[V];
		colors=new int[V];
		for(int v=0;v<V;v++)
		{
     
			if(!visited[v])
			{
     
				if(!dfs(v,0))
				{
     
					return false;
				}
			}
		}
		return true;
	}
	
	private boolean dfs(int v,int color)
	{
     
		visited[v]=true;
		colors[v]=color;
		for(int w:graph[v])
		{
     
			if(!visited[w])
			{
     
				if(!dfs(w,1-color))
					return false;
			}
			else
			{
     
				if(colors[v]==colors[w])
				{
     
					return false;
				}
			}
		}
		return true;
	
    }
}