使用dfs检查图是否为二部图

def isBipartite(graph):
    n = len(graph)
    colors = [0] * n  # 0表示未标记，1表示集合A，-1表示集合B

    def dfs(node, color):
        colors[node] = color
        for neighbor in graph[node]:
            if colors[neighbor] == color:
                return False
            if colors[neighbor] == 0 and not dfs(neighbor, -color):
                return False
        return True

    for i in range(n):
        if colors[i] == 0 and not dfs(i, 1):
            return False
    return True