leetcode——15.三数之和

class Solution:
    def threeSum(self, nums) :
        nums.sort()
        #print(nums)
        nums1=[]
        s=[]
        if nums.count(0)>=3:
            s.append([0,0,0])
        for i in range(len(nums)-2):
            #print(‘i= ‘+str(i))
            for j in range(i+1,len(nums)-1):
                #print(‘j= ‘+str(j))
                if 0-(nums[i]+nums[j]) in nums[j+1:]:
                    if [nums[i],nums[j],0-(nums[i]+nums[j])] not in s:
                        s.append([nums[i],nums[j],0-(nums[i]+nums[j])])
        return s

class Solution:
    def threeSum(self, nums) :
        nums.sort()
        #print(nums)
        nums1=[]
        nums2=[]
        s=[]
        if nums.count(0)>=3:
            s.append([0,0,0])
        for i in range(len(nums)-1,-1,-1):
            if nums[i]>0:
                nums1.append(nums[i])
            else:
                nums2.append(nums[i])
        #print(nums1)#存放正数
        #print(nums2)#存放非正数
        
        
        for i in range(len(nums)-1):
            if i>0:
                if nums[i]==nums[i-1]:
                    continue#如果是相同的数，则跳过
            left,right=i+1,len(nums)-1#两个指针
            #print(‘i= ‘+str(i))
            while left<right: #左指针小于右指针
                sums=nums[i]+nums[left]+nums[right]
                #print(‘sums= ‘+str(sums))
                if right<len(nums2):
                    break
                if sums==0:
                    s.append([nums[left],nums[i],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
                elif sums<0:
                    left+=1
                elif sums>0:
                    right-=1
        return s