[Letcode 15]税金の合計

# 배열을 입력받아 합으로 0을 만들 수 있는 3개의 엘리먼트를 출력
# nums = [-1,0,1,2,-1,-4]
# nums = [-4,-1,-1,0,1,2]
def threeSum(nums):
    result = []
    left, right = 0, len(nums)-1
    flipped = 0
    nums.sort()

    while not left == right:
        twoSum = nums[left] + nums[right]

        if -twoSum in nums[left + 1 : right] and \
                [nums[left],-twoSum,nums[right]] not in result:
            result.append([nums[left],-twoSum,nums[right]])

        if flipped == 0:
            left += 1
            flipped = 1
        else:
            right -= 1
            flipped = 0

    return result

if __name__ =="__main__":
    nums = [-1,0,1,2,-1,-4]
    print(threeSum(nums))

    # output
    #
    # [
    #     [-1,0,1],
    #     [-1,-1,2]
    # ]

IndexError: list index out of range
twoSum = nums[left] + nums[right]
Line 9 in threeSum (Solution.py)

def threeSum_brute_force(nums):
    result = []
    nums.sort()

    for i in range(len(nums)-2):
        if i>0 and nums[i] == nums[i-1]:
            continue
        for j in range(i+1, len(nums)-1):
            if j > i+1 and nums[j] == nums[j-1]:
                continue
            for k in range(j+1, len(nums)):
                if k > j+1 and nums[k] == nums[k-1]:
                    continue
                if nums[i] + nums[j] + nums[k] == 0:
                    result.append((nums[i], nums[j], nums[k]))
                
    return result

タイムアウト
ダブルポインタマージ計算

# 배열을 입력받아 합으로 0을 만들 수 있는 3개의 엘리먼트를 출력
# nums = [-2, 0, 1, 1, 2]
# nums.sort
# nums = [-2,0,1,1,2]
def threeSum_two_pointer(nums):
    results = []
	nums.sort()
    for i in range(len(nums)-2):
        if i > 0 and nums[i] == nums[i-1]:
            continue
        left,right = i+1, len(nums) -1
        while left < right:
            sum = nums[i] + nums[left] + nums[right]

            if sum < 0:
                left += 1
            elif sum > 0:
                right -= 1
            else:
                # sum == 0
                results.append((nums[i],nums[left],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
    return results


def threeSum_brute_force(nums):
    result = []
    nums.sort()

    for i in range(len(nums)-2):
        if i>0 and nums[i] == nums[i-1]:
            continue
        for j in range(i+1, len(nums)-1):
            if j > i+1 and nums[j] == nums[j-1]:
                continue
            for k in range(j+1, len(nums)):
                if k > j+1 and nums[k] == nums[k-1]:
                    continue
                if nums[i] + nums[j] + nums[k] == 0:
                    result.append((nums[i], nums[j], nums[k]))

    return result
if __name__ =="__main__":
    nums = [-2,0,1,1,2]
    print(threeSum_two_pointer(nums))

    # output
    #
    # [
    #     [-1,0,1],
    #     [-1,-1,2]
    # ]