判断二分图

//判断二分图
class TwoColor1 {
	private boolean[] marked;
	private boolean[] color;
	private boolean isTwoColorable = true;
	
	public TwoColor1(Graph G) {
		marked = new boolean[G.V()];
		color = new boolean[G.V()];
		
		for (int s = 0;s < G.V();++s)
			if (!marked[s])
				dfs(G, s);
	}
	
	
	private void dfs(Graph G, int s) {
		marked[s] = true;
		
		for (int v: G.adj(s)) {
			if (!marked[v]) {
//				if (color[s] == true)
//					color[v] = false;
//				else
//					color[v] = true;
				
				color[v] = !color[s];
				
				dfs(G, v);
			}
			else if (color[v] == color[s])
				isTwoColorable = false;
		}
	}
	
	public boolean isBipartite() {
		return isTwoColorable;
	}
}