Python_Hot100

Fri, 22 May 2026 20:21:35 +0800

Python Hot100 学习笔记

这篇是我刷 Hot100 的总览页。
我会把每道题单独存到此篇笔记目录下的 .py 文件，并由页面自动读取展示。

代码

1. 两数之和

class Solution(object):
 def twoSum(self, nums, target):
 l = len(nums)
 hashtable = dict()
 
 for i in range(l):
 if target - nums[i] in hashtable:
 return [hashtable[target - nums[i]], i]

 hashtable[nums[i]] = i

 return []

49. 字母异位词分组

class Solution(object):
 def groupAnagrams(self, strs):
 mp = dict()

 for s in strs:
 key = "".join(sorted(s))
 if key not in mp:
 mp[key] = []
 mp[key].append(s)

 return list(mp.values())

128. 最长连续序列

class Solution:
 def longestConsecutive(self, nums: List[int]) -> int:
 hashset = set(nums)
 maxlen = 0

 for num in nums :
 if num-1 not in hashset :
 nowlen = 1
 nex = num+1

 while nex in hashset :
 nex += 1
 nowlen += 1

 maxlen = max(nowlen,maxlen)
 
 return maxlen

283. 移动零

class Solution:
 def moveZeroes(self, nums: List[int]) -> None:
 length = len(nums)
 putindex = 0

 # 将非零元素依次放在前面
 for i in range(length):
 while putindex < length and nums[putindex] == 0:
 putindex += 1

 if putindex == length:
 nums[i] = 0
 else:
 nums[i] = nums[putindex]
 putindex += 1

11. 盛最多水的容器

class Solution:
 def maxArea(self, height: List[int]) -> int:
 left = 0
 right = len(height)-1
 maxArea = 0

 while left < right :
 area = (right-left) * min(height[right] , height[left])
 maxArea = max( maxArea , area)

 if height[right] < height[left] :
 right -= 1
 else :
 left += 1

 return maxArea

15. 三数之和

class Solution:
 def threeSum(self, nums: list[int]) -> list[list[int]]:
 # 双重for + set找need 有重复
 # 应该使用排序 + 双指针
 l = len(nums)
 nums.sort()
 ans = []
 for i in range(l) :
 if i > 0 and nums[i] == nums[i-1] :
 continue
 need = -nums[i]
 left = i+1
 right = l-1
 while left < right :
 if nums[left]+nums[right] > need : 
 right -= 1
 elif nums[left]+nums[right] < need :
 left += 1
 else :
 ans.append([-need , nums[left] , nums[right]])
 while left < right and nums[left] == nums[left + 1]: left += 1
 while left < right and nums[right] == nums[right - 1]: right -= 1
 left += 1
 right -= 1
 
 return ans

42. 接雨水

class Solution:
 def trap(self, height: List[int]) -> int:
 l = len(height)
 pre = 0
 preheight = [0]*l

 for i in range(l) :
 pre = max(height[i],pre)
 preheight[i] = pre

 ans = 0
 nex = 0
 for j in range(l-1 , -1, -1) :
 nex = max(height[j],nex)
 ans += min(nex,preheight[j])-height[j]
 
 return ans

3. 无重复字符的最长子串

class Solution:
 def lengthOfLongestSubstring(self, s: str) -> int:
 if not s :
 return 0
 mp = {}
 star , l = 0 , 1
 # map中存在即重复 新的star = key+1
 for i in range(len(s)) :
 c = s[i]
 if c not in mp or mp[c] < star :
 l = max(l , i-star+1)
 mp[c] = i
 else :
 star = mp[c]+1
 mp[c] = i

 return l

438. 找到字符串中所有字母异位词

class Solution:
 def findAnagrams(self, s: str, p: str) -> List[int]:
 sl,pl = len(s),len(p)
 if sl < pl :
 return [] 

 sMap,pMap = [0]*26 , [0]*26
 ans = []
 for i in range(pl) :
 sMap[ ord(s[i]) - ord('a') ] += 1
 pMap[ ord(p[i]) - ord('a') ] += 1

 if sMap == pMap :
 ans.append(0)

 for i in range(0 , sl-pl) :
 sMap[ ord(s[i])-ord('a') ] -= 1
 sMap[ord(s[i+pl])-ord('a')] +=1

 if sMap == pMap :
 ans.append(i+1)

 return ans

560. 和为 K 的子数组

class Solution:
 def subarraySum(self, nums: List[int], k: int) -> int:
 ans , nowsum = 0, 0
 mp = {}
 mp[0] = 1
 for num in nums :
 nowsum += num
 need = nowsum - k
 if need in mp :
 ans += mp[need]
 mp[nowsum] = mp.get(nowsum , 0) +1 
 return ans

239. 滑动窗口最大值

class Solution:
 def maxSlidingWindow(self, nums: List[int], k: int) -> List[int]:
 l = len(nums)
 if k > l :
 return []
 left = 0
 heap = []
 ans = []
 for i in range(l) :
 # 存当前的元素
 heapq.heappush(heap , (-nums[i] , i))
 if i >= k-1 :
 # 满了 存 拿 移动left
 while heap[0][1] < left :
 heapq.heappop(heap)
 ans.append(-heap[0][0])
 left += 1 
 return ans
 #也可以存递减的下标

76. 最小覆盖子串

class Solution:
 def minWindow(self, s: str, t: str) -> str:
 if len(t) > len(s) :
 return ""

 tmap ={}
 for tchar in t :
 tmap[tchar] = tmap.get(tchar, 0) + 1
 needchar = len(tmap)
 left , star = 0 , -1
 minLength = len(s) + 1
 for right in range(len(s)) :
 addchar = s[right]
 if addchar in tmap:
 tmap[addchar] -= 1
 if tmap[addchar] == 0 : needchar -= 1
 while needchar == 0 :
 # 移除前面的无用字母 
 if s[left] not in tmap :
 left += 1
 # 以及多余字母
 elif tmap[s[left]] < 0 :
 tmap[s[left]] += 1
 left += 1
 # 当前最短有效
 else :
 if right-left+1 < minLength :
 minLength = right-left+1
 star = left
 # 记录后 删除第一个有效字母
 tmap[s[left]] += 1
 needchar += 1
 left += 1
 if star == -1 : return ""
 return s[star : star+minLength]

53. 最大子数组和

class Solution:
 def maxSubArray(self, nums: List[int]) -> int:
 maxsum,nowsum = nums[0],0
 
 for right in range(len(nums)) :
 nowsum += nums[right]
 # 更新最大值
 maxsum = max(maxsum,nowsum)
 # 如果当前和小于0 就丢弃之前的和 从下一个开始
 if nowsum < 0:
 nowsum = 0

 return maxsum

56. 合并区间

class Solution:
 def merge(self, intervals: List[List[int]]) -> List[List[int]]:
 pq = []
 ans = []
 for interval in intervals :
 heapq.heappush(pq,interval)
 while pq :
 interval = heapq.heappop(pq)
 while pq and pq[0][0] <= interval[1] :
 add = heapq.heappop(pq)
 interval[1] = max (interval[1],add[1])
 ans.append(interval)
 return ans

记录方式

将道题结果 .py 文件存入hoot100笔记统计目录下，扫描全部py文件自动添加显示
代码都是 leetcode 过了提交测试的，但是思路并不一定是最佳思路，仅为自己过程记录
如果你发现了某个代码有问题，可以在背地里偷偷笑我，因为我的博客里没有添加评论功能

Hot100 on XEDCZQ的博客

Python_Hot100

Python Hot100 学习笔记

目录

代码

1. 两数之和

49. 字母异位词分组

128. 最长连续序列

283. 移动零

11. 盛最多水的容器

15. 三数之和

42. 接雨水

3. 无重复字符的最长子串

438. 找到字符串中所有字母异位词

560. 和为 K 的子数组

239. 滑动窗口最大值

76. 最小覆盖子串

53. 最大子数组和

56. 合并区间

记录方式