Merge pull request #69 from Boy-timi/master

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Yudong Jin 2022-12-04 01:33:19 +08:00 committed by GitHub
commit 37fd281d72
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3 changed files with 106 additions and 6 deletions

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'''
File: binary_search.py
Created Time: 2022-11-25
Author: Krahets (krahets@163.com)
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 include import *
""" 二分查找(双闭区间) """
def binary_search(nums, target):
# 初始化双闭区间 [0, n-1] ,即 i, j 分别指向数组首元素、尾元素
i, j = 0, len(nums) - 1
while i <= j:
m = (i + j) // 2 # 计算中点索引 m
if nums[m] < target: # 此情况说明 target 在区间 [m+1, j] 中
i = m + 1
elif nums[m] > target: # 此情况说明 target 在区间 [i, m-1] 中
j = m - 1
else:
return m # 找到目标元素,返回其索引
return -1 # 未找到目标元素,返回 -1
""" 二分查找(左闭右开) """
def binary_search1(nums, target):
# 初始化左闭右开 [0, n) ,即 i, j 分别指向数组首元素、尾元素+1
i, j = 0, len(nums)
# 循环,当搜索区间为空时跳出(当 i = j 时为空)
while i < j:
m = (i + j) // 2 # 计算中点索引 m
if nums[m] < target: # 此情况说明 target 在区间 [m+1, j) 中
i = m + 1
elif nums[m] > target: # 此情况说明 target 在区间 [i, m) 中
j = m
else: # 找到目标元素,返回其索引
return m
return -1 # 未找到目标元素,返回 -1
if __name__ == '__main__':
target = 6
nums = [1, 3, 6, 8, 12, 15, 23, 67, 70, 92]
# 二分查找(双闭区间)
index = binary_search(nums, target)
print("目标元素 6 的索引 = ", index)
# 二分查找(左闭右开)
index = binary_search1(nums, target)
print("目标元素 6 的索引 = ", index)

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'''
File: hashing_search.py
Created Time: 2022-11-25
Author: Krahets (krahets@163.com)
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 include import *
""" 哈希查找(数组) """
def hashing_search(map,target):
# 哈希表的 key: 目标元素value: 索引
# 若哈希表中无此 key ,返回 -1
return map.get(target,-1)
""" 哈希查找(链表) """
def hashing_search1(map,target):
# 哈希表的 key: 目标元素value: 节点对象
# 若哈希表中无此 key ,返回 -1
return map.get(target,-1)
if __name__=='__main__':
target=3
# 哈希查找(数组)
nums=[1, 5, 3, 2, 4, 7, 5, 9, 10, 8]
map=dict() # 初始化哈希表
for i in range(len(nums)):
map[nums[i]]=i # key: 元素value: 索引
index=hashing_search(map,target)
print("目标元素 3 的索引 = " ,index)
# 哈希查找(链表)
head=list_to_linked_list(nums)
map1=dict() # 初始化哈希表
while head:
map1[head.val]=head # key: 结点值value: 结点
head=head.next
node=hashing_search1(map1,target)
print("目标结点值 3 的对应结点对象为 " , node)

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'''
File: linear_search.py
Created Time: 2022-11-25
Author: Krahets (krahets@163.com)
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 include import *
""" 线性查找(数组) """
def linear_search(nums,target):
# 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
""" 线性查找(链表) """
def linear_search_by_link(head,target):
# 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 (Python为None)
if __name__=='__main__':
target=3
# 在数组中执行线性查找
nums=[1, 5, 3, 2, 4, 7, 5, 9, 10, 8]
index=linear_search(nums,target)
print("目标元素 3 的索引 = " ,index)
# 在链表中执行线性查找
head=list_to_linked_list(nums)
node=linear_search_by_link(head,target)
print("目标结点值 3 的对应结点对象为 " ,node)