题解 | #三数之和#

#
# 代码中的类名、方法名、参数名已经指定，请勿修改，直接返回方法规定的值即可
#
# 
# @param num int整型一维数组 
# @return int整型二维数组
#
class Solution:
    def threeSum(self , num: List[int]) -> List[List[int]]:
        # write code here
        res = []
        if not num or len(num)<3:
            return res
        num = sorted(num)
        print(num)
        for i in range(len(num)-2):
            if i>0 and num[i]==num[i-1]:
                continue
            left,right = i+1,len(num)-1
            target = -num[i]
            while left!=right:
                if num[left]+num[right]==-num[i]:
                    res.append([num[i],num[left],num[right]])
                    left += 1
                    while left!=right and num[left]==num[left-1]:
                        left += 1
                    continue
                if num[left]+num[right]<-num[i]:
                    left += 1
                else:
                    right -= 1
        return res