[Python手撕]判断二分图

class Solution:
    def isBipartite(self, graph: List[List[int]]) -> bool:

        def bfs(i):
            color[i] = 1
            queue = [(i,1)]
            while queue:
                t,c = queue.pop(0)
                
                nc = 0
                if c == 1:
                    nc = -1
                else:
                    nc = 1

                for nt in graph[t]:
                    if color[nt] != 0 and color[nt] == c:
                        return False
                    elif color[nt] == 0:
                        color[nt] = nc
                        queue.append((nt,nc))
            return True
                            

        n = len(graph)
        color = [0] * n
        for i in range(n):
            if color[i] == 0:
                if not bfs(i):
                    return False
        return True