import time
import random
import csv
import matplotlib.pyplot as plt
import numpy as np

def ll_insert(head, name, phone):
    new_node = {'name': name, 'phone': phone, 'next': None}
    if head is None:
        return new_node
    current = head
    while current:
        if current['name'] == name:
            current['phone'] = phone
            return head
        if current['next'] is None:
            current['next'] = new_node
            return head
        current = current['next']
    return head

def ll_find(head, name):
    current = head
    while current:
        if current['name'] == name:
            return current['phone']
        current = current['next']
    return None

def ll_delete(head, name):
    if head is None:
        return None
    if head['name'] == name:
        return head['next']
    current = head
    while current['next']:
        if current['next']['name'] == name:
            current['next'] = current['next']['next']
            return head
        current = current['next']
    return head

def ll_list_all(head):
    records = []
    current = head
    while current:
        records.append((current['name'], current['phone']))
        current = current['next']
    return sorted(records, key=lambda x: x[0])