[5/20] 785. Is Graph Bipartite?

# Time Complexity: O(n + e), Space Compleixty: O(n)

class Solution:
    def isBipartite(self, graph: List[List[int]]) -> bool:
        n = len(graph)
        colors = [0] * n
        
        def dfs(u, color) -> bool:
            if (colors[u] != 0):
                return colors[u] == color

            colors[u] = color
            for v in graph[u]:
                if (not dfs(v, -color)):
                    return False
            return True
        
        for u in range(n):
            if (colors[u] == 0 and not dfs(u, 1)):
                return False
        return True