[LeetCode]题15:3Sum

第一次解：

        res = []
        nums.sort()
        if len(nums)<3:return []
        for i in range(len(nums)-2):
            left = i+1
            right = len(nums)-1
            while left < right:
                val = nums[i]+nums[left]+nums[right]
                if val==0 and [nums[i],nums[left],nums[right]] not in res:
                    res.append([nums[i],nums[left],nums[right]])
                elif val<0:
                    left += 1
                else:
                    right -=1
        return res

超时。。。然后调整

nums.sort()
        res = []

        for i in range(len(nums) - 2):
            if i > 0 and nums[i-1] == nums[i]: continue
            l, r = i + 1, len(nums) - 1
            while l < r:
                s = nums[i] + nums[l] + nums[r]
                if s == 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 s < 0:
                    l += 1
                else:
                   r -= 1
        return res

acc了