leetcode学习笔记(两数组中位数/三数之和/颜色分类)

class Solution:
    def findMedianSortedArrays(self, nums1, nums2):
        nums1.extend(nums2)
        nums1.sort()
        if len(nums1)%2 == 0:
            i = int(len(nums1)/2)
            return (nums1[i-1] +nums1[i])/2
        else:
            i = int((len(nums1)+1)/2)
            return nums1[i-1]

	class Solution:
    def findMedianSortedArrays(self, nums1: List[int], nums2: List[int]) -> float:
        len1 = len(nums1)
        len2 = len(nums2)
        flag1 = 0
        flag2 = 0
        conlist = []
        while(True):
            if flag1 < len1 and flag2 < len2:
                if nums1[flag1] < nums2[flag2]:
                    conlist.append(nums1[flag1])
                    flag1 +=1
                else:
                    conlist.append(nums2[flag2])
                    flag2 +=1
            elif flag1 >= len1 and flag2 < len2:
                conlist.append(nums2[flag2])
                flag2 +=1
            elif flag1 < len1 and flag2 >= len2:
                conlist.append(nums1[flag1])
                flag1 +=1
            else:
                break
        if (len1+len2)%2!=0:
            return conlist[(len1+len2)//2]
        else:
            return (conlist[(len1+len2)//2-1] + conlist[(len1+len2)//2])/2
        return conlist[(len1+len2)//2]

class Solution:
    def threeSum(self, nums: List[int]) -> List[List[int]]:
        result = []
        lens = len(nums)
        for i in range(lens):
            for j in range(i+1,lens):
                a = nums[j+1:]
                if -(nums[i]+nums[j]) in a:
                    result.append([nums[i],nums[j],-(nums[i]+nums[j])])
        re1 = []
        for re in result:
            re.sort()
            if re not in re1:
                re1.append(re)
        return re1

class Solution:
    def threeSum(self, nums: List[int]) -> List[List[int]]:
        if len(nums) < 3:
            return []
        nums.sort()
        res = []
        for i in range(len(nums)):
            if nums[i] > 0:
                return res #如果剩下的数列第一个数字就大于0
            if i > 0 and nums[i] == nums[i-1]:
                continue
            else:
                L = i+1
                R = len(nums)-1
                while L 0: 
                        R -= 1
                        
        return res

class Solution:
    def sortColors(self, nums: List[int]) -> None:
        nums.sort()
        return nums

class Solution:
    def sortColors(self, nums: List[int]) -> None:
        n = len(nums)
        i = 0
        p0, p2 = 0, n-1 
               
        while i <= p2:
            while i <= p2 and nums[i] == 2:
                nums[i], nums[p2] = nums[p2], nums[i]#把2换到最后
                p2 -= 1
            if nums[i] == 0:
                nums[i], nums[p0] = nums[p0], nums[i]#把0换到最开头
                p0 += 1
            i += 1

        return nums