hello-algo/codes/python/chapter_searching/linear_search.py

"""
File: linear_search.py
Created Time: 2022-11-26
Author: timi (xisunyy@163.com)
"""

import sys, os.path as osp
sys.path.append(osp.dirname(osp.dirname(osp.abspath(__file__))))
from modules import *

def linear_search_array(nums: List[int], target: int) -> int:
    """ 线性查找（数组） """
    # 遍历数组
    for i in range(len(nums)):
        if nums[i] == target:  # 找到目标元素，返回其索引
            return i
    return -1                  # 未找到目标元素，返回 -1

def linear_search_linkedlist(head: ListNode, target: int) -> Optional[ListNode]:
    """ 线性查找（链表） """
    # 遍历链表
    while head:
        if head.val == target: # 找到目标结点，返回之
            return head
        head = head.next
    return None                # 未找到目标结点，返回 None


""" Driver Code """
if __name__ == '__main__':
    target: int = 3
    
    # 在数组中执行线性查找
    nums: List[int] = [1, 5, 3, 2, 4, 7, 5, 9, 10, 8]
    index: int = linear_search_array(nums, target)
    print("目标元素 3 的索引 =", index)

    # 在链表中执行线性查找
    head: ListNode = list_to_linked_list(nums)
    node: Optional[ListNode] = linear_search_linkedlist(head, target)
    print("目标结点值 3 的对应结点对象为", node)