leetcode打卡
class Solution:
def twoSum(self, nums: List[int], target: int) -> List[int]:
res=[]
l,r=0,len(nums)-1
nums.sort()
nums_copy=nums.copy()
sameFalg=True
while l<r:
if nums[l]+nums[r]==target:
break
elif nums[l]+nums[r]>target:
r-=1
else:
l+=1
for i in range(len(nums)):
if nums_copy[i]==nums[l] and sameFalg:
res.append(i)
sameFalg=False
elif nums_copy[i]==nums[r]:
res.append(i)
return res
15
class Solution:
def threeSum(self, nums: [int]) -> [[int]]:
nums.sort()
res = []
for i in range(len(nums)-2):
# 因为是排序好的数组，如果最小的都大于0可以直接排除
if nums[i] > 0: break
# 排除i的重复值
if i > 0 and nums[i] == nums[i-1]: continue
l,r = i+1, len(nums)-1
while l < r:
sum = nums[i] + nums[l] + nums[r]
if sum == 0:
res.append([nums[i],nums[l],nums[r]])
l += 1
r -= 1
while l < r and nums[l] == nums[l-1]: l += 1
while l < r and nums[r] == nums[r+1]: r -= 1
elif sum < 0:
l += 1
else:
r -= 1
return res
class Solution:
def fourSum(self, nums: List[int], target: int) -> List[List[int]]:
nums.sort()
res = []
if len(nums) < 4: return res
if len(nums) == 4 and sum(nums) == target:
res.append(nums)
return res
for i in range(len(nums)-3):
if i > 0 and nums[i] == nums[i-1]: continue
for j in range(i+1,len(nums)-2):
if j > i+1 and nums[j] == nums[j-1]: continue
l,r = j+1, len(nums)-1
while l < r:
sum_value = nums[i] + nums[j] + nums[l] + nums[r]
if sum_value == target:
res.append([nums[i],nums[j],nums[l],nums[r]])
l += 1
r -= 1
while l < r and nums[l] == nums[l-1]: l += 1
while l < r and nums[r] == nums[r+1]: r -= 1
elif sum_value < target:
l += 1
else:
r -= 1
return res
class Solution:
def threeSumClosest(self, nums: List[int], target: int) -> int:
nums.sort()
diff = abs(nums[0]+nums[1]+nums[2]-target)
res = nums[0] + nums[1] + nums[2]
for i in range(len(nums)):
l,r = i+1,len(nums)-1
t = target - nums[i]
while l < r:
if nums[l] + nums[r] == t:
return nums[i] + t
else:
if abs(nums[l]+nums[r]-t) < diff:
diff = abs(nums[l]+nums[r]-t)
res = nums[i]+nums[l]+nums[r]
if nums[l]+nums[r] < t:
l += 1
else:
r -= 1
return res
454
class Solution:
def fourSumCount(self, A: List[int], B: List[int], C: List[int], D: List[int]) -> int:
from collections import Counter
record = Counter()
for i in range(len(A)):
for j in range(len(B)):
record[A[i]+B[j]] += 1
res = 0
for i in range(len(C)):
for j in range(len(D)):
find_num = 0 - C[i] - D[j]
if record.get(find_num) != None:
res += record[find_num]
return res
class Solution:
def groupAnagrams(self, strs: List[str]) -> List[List[str]]:
from collections import defaultdict
strs_dict = defaultdict(list)
res = []
for str in strs:
key = ''.join(sorted(list(str)))
strs_dict[key] += str.split(',')
for v in strs_dict.values():
res.append(v)
return res
class Solution:
def numberOfBoomerangs(self, points: List[List[int]]) -> int:
res = 0
from collections import Counter
for i in points:
record = Counter()
for j in points:
if i != j:
record[self.dis(i,j)] += 1
for k,v in record.items():
res += v*(v-1)
return res
def dis(self,point1,point2):
return (point1[0]-point2[0]) ** 2 + (point1[1]-point2[1]) ** 2
class Solution:
def maxPoints(self,points):
if len(points) <= 1: #对边界情况进行判断，如果初始长度小于等于1,则直接返回len
return len(points)
res = 0
from collections import defaultdict
for i in range(len(points)):
record = defaultdict(int)
samepoint = 0 #对相同元素的情况单独考虑
for j in range(len(points)):
if points[i][0] == points[j][0] and points[i][1] == points[j][1]:
samepoint += 1
else:
record[self.get_Slope(points,i,j)] += 1
for v in record.values():
res = max(res, v+samepoint)
res = max(res, samepoint)
return res
def get_Slope(self,points,i,j): #直线为垂直的情况
if points[i][1] - points[j][1] == 0:
return float('Inf')
else:
return (points[i][0] - points[j][0]) / (points[i][1] - points[j][1])