<div id="readability-page-1" class="page"><div>
            <h2 id="%EB%AC%B8%EC%A0%9C">문제</h2><figure><a href="https://leetcode.com/problems/two-sum-ii-input-array-is-sorted/"><div><p>Loading...</p><p>Level up your coding skills and quickly land a job. This is the best place to expand your knowledge and get prepared for your next interview.</p><p><img src="https://leetcode.com/favicon-192x192.png"><span>LeetCode</span></p></div><p><img src="https://leetcode.com/static/images/LeetCode_Sharing.png"></p></a></figure><h2 id="%ED%92%80%EC%9D%B4">풀이</h2><p>브루트 포스</p><pre><code>class Solution:
    def twoSum(self, numbers: List[int], target: int) -&gt; List[int]:
        for idx1, num1 in enumerate(numbers):
            for idx2, num2 in enumerate(numbers[idx1 + 1 :]):
                if num1 + num2 &gt; target:
                    break
                if num1 + num2 == target:
                    return sorted([idx1 + 1, idx1 + idx2 + 2])</code></pre><p>Binary search</p><pre><code>class Solution:
    def twoSum(self, numbers: List[int], target: int) -&gt; List[int]:
        for idx, num in enumerate(numbers):
            new_target = target - num

            left, right = idx + 1, len(numbers) - 1
            while left &lt;= right:
                mid = (left + right) // 2

                if numbers[mid] &lt; new_target:
                    left = mid + 1
                elif numbers[mid] &gt; new_target:
                    right = mid - 1
                else:
                    return [idx + 1, mid + 1]</code></pre><p>Two pointers</p><pre><code>class Solution:
    def twoSum(self, numbers: List[int], target: int) -&gt; List[int]:
        left, right = 0, len(numbers) - 1
        while left != right:
            if numbers[left] + numbers[right] &lt; target:
                left += 1
            elif numbers[left] + numbers[right] &gt; target:
                right -= 1
            else:
                return [left + 1, right + 1]</code></pre>
        </div></div>

일시불 프로그래밍

문제
풀이
브루트 포스
class Solution:
    def twoSum(self, numbers: List[int], target: int) -> List[int]:
        for idx1, num1 in enumerate(numbers):
            for idx2, num2 in enumerate(numbers[idx1 + 1 :]):
                if num1 + num2 > target:
                    break
                if num1 + num2 == target:
                    return sorted([idx1 + 1, idx1 + idx2 + 2])
Binary search
class Solution:
    def twoSum(self, numbers: List[int], target: int) -> List[int]:
        for idx, num in enumerate(numbers):
            new_target = target - num
            left, right = idx + 1, len(numbers) - 1
            while left <= right:
                mid = (left + right) // 2
                if numbers[mid] < new_target:
                    left = mid + 1
                elif numbers[mid] > new_target:
                    right = mid - 1
                else:
                    return [idx + 1, mid + 1]
Two pointers
class Solution:
    def twoSum(self, numbers: List[int], target: int) -> List[int]:
        left, right = 0, len(numbers) - 1
        while left != right:
            if numbers[left] + numbers[right] < target:
                left += 1
            elif numbers[left] + numbers[right] > target:
                right -= 1
            else:
                return [left + 1, right + 1]

Leetcode - 167. Two Sum II - Input array is sorted

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