把注释中文改成英文

Sure, here are the algorithms with comments in English:

### Depth-First Search Algorithm

# Define a graph class
class Graph:
    def __init__(self, vertices):
        self.vertices = vertices
        self.adjacency_list = [[] for _ in range(vertices)]
        self.visited = [False] * vertices
 
    def add_edge(self, u, v):
        self.adjacency_list[u].append(v)
 
    def dfs(self, start, end):
        # Mark the start node as visited
        self.visited[start] = True
        # Traverse the neighbors of the start node
        for i in self.adjacency_list[start]:
            # If the neighbor has not been visited, recursively visit it
            if not self.visited[i]:
                self.dfs(i, end)
        # If the end node has been visited, there exists a path
        if self.visited[end]:
            return True
        # If the end node has not been visited, there does not exist a path
        return False

### Breadth-First Search Algorithm

# Define a graph class
class Graph:
    def __init__(self, vertices):
        self.vertices = vertices
        self.adjacency_list = [[] for _ in range(vertices)]
 
    def add_edge(self, u, v):
        self.adjacency_list[u].append(v)
 
    def bfs(self, start, end):
        # Create a queue and add the start node to the queue
        queue = [start]
        # Create a visited list to keep track of visited nodes
        visited = [False] * self.vertices
        visited[start] = True
 
        while queue:
            # Dequeue a node from the queue
            node = queue.pop(0)
            # Traverse the neighbors of the node
            for i in self.adjacency_list[node]:
                # If the neighbor has not been visited, add it to the queue and mark it as visited
                if not visited[i]:
                    queue.append(i)
                    visited[i] = True
                    # If the end node is found, there exists a path
                    if i == end:
                        return True
        # If the end node is not found after traversing the entire graph, there does not exist a path
        return False

I hope this helps!