answer:class Node: def __init__(self, value): self.value = value self.next = None class Queue: def __init__(self): self.front = None self.rear = None def enqueue(self, value): new_node = Node(value) if self.rear is None: self.front = self.rear = new_node return self.rear.next = new_node self.rear = new_node def dequeue(self): if self.is_empty(): raise IndexError("Dequeue from empty queue") temp = self.front self.front = temp.next if self.front is None: self.rear = None return temp.value def is_empty(self): return self.front is None def peek(self): if self.is_empty(): raise IndexError("Peek from empty queue") return self.front.value

answer:def calculate_final_score(scores): Calculates the average of valid scores in the list, rounded to two decimal places. A valid score is between 0 and 100 inclusive. Parameters: scores (list): A list of integers or floats representing the scores. Returns: float: The average of valid scores rounded to two decimal places. Raises: ValueError: If there are no valid scores in the list. valid_scores = [score for score in scores if 0 <= score <= 100] if not valid_scores: raise ValueError("No valid scores available.") average_score = sum(valid_scores) / len(valid_scores) return round(average_score, 2)

answer:from typing import List, Tuple from collections import defaultdict, deque def reconstruct_itinerary(tickets: List[Tuple[str, str]]) -> List[str]: graph = defaultdict(deque) # Create the graph, sorting each adjacency list lexicographically for start, end in sorted(tickets): graph[start].append(end) itinerary = [] def dfs(airport): while graph[airport]: next_airport = graph[airport].popleft() dfs(next_airport) itinerary.append(airport) # Start the journey from 'JFK' dfs('JFK') # Since we add airports after visiting the end of their edges, reverse the result return itinerary[::-1]

answer:def min_coins(coins, sum_amount): Calculate the minimum number of coins required to make the given sum. Args: - coins (list[int]): Available denominations of coins. - sum_amount (int): Target sum to be made using the coins. Returns: - int: Minimum number of coins needed to reach the given sum, or -1 if it is not possible. dp = [float('inf')] * (sum_amount + 1) dp[0] = 0 # Zero coins needed to make sum 0 for coin in coins: for x in range(coin, sum_amount + 1): dp[x] = min(dp[x], dp[x - coin] + 1) return dp[sum_amount] if dp[sum_amount] != float('inf') else -1 def get_coin_combination(coins, sum_amount): Retrieve the combination of coins that make up the given sum using the minimum number of coins. Args: - coins (list[int]): Available denominations of coins. - sum_amount (int): Target sum to be made using the coins. Returns: - list[int]: A list of coins that sums up to the given sum using the minimum number of coins, or an empty list if it is not possible. dp = [float('inf')] * (sum_amount + 1) dp[0] = 0 # Zero coins needed to make sum 0 backtrack = [-1] * (sum_amount + 1) for coin in coins: for x in range(coin, sum_amount + 1): if dp[x - coin] + 1 < dp[x]: dp[x] = dp[x - coin] + 1 backtrack[x] = coin if dp[sum_amount] == float('inf'): return [] result = [] while sum_amount > 0: coin = backtrack[sum_amount] result.append(coin) sum_amount -= coin return result