{ "data": { "question": { "questionId": "1", "questionFrontendId": "1", "boundTopicId": null, "title": "Two Sum", "titleSlug": "two-sum", "content": "

Given an array of integers nums and an integer target, return indices of the two numbers such that they add up to target.

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You may assume that each input would have exactly one solution, and you may not use the same element twice.

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You can return the answer in any order.

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Example 1:

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\nInput: nums = [2,7,11,15], target = 9\nOutput: [0,1]\nExplanation: Because nums[0] + nums[1] == 9, we return [0, 1].\n
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Example 2:

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\nInput: nums = [3,2,4], target = 6\nOutput: [1,2]\n
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Example 3:

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\nInput: nums = [3,3], target = 6\nOutput: [0,1]\n
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Constraints:

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\nFollow-up: Can you come up with an algorithm that is less than O(n2) time complexity?", "translatedTitle": null, "translatedContent": null, "isPaidOnly": false, "difficulty": "Easy", "likes": 53548, "dislikes": 1773, "isLiked": null, "similarQuestions": "[{\"title\": \"3Sum\", \"titleSlug\": \"3sum\", \"difficulty\": \"Medium\", \"translatedTitle\": null}, {\"title\": \"4Sum\", \"titleSlug\": \"4sum\", \"difficulty\": \"Medium\", \"translatedTitle\": null}, {\"title\": \"Two Sum II - Input Array Is Sorted\", \"titleSlug\": \"two-sum-ii-input-array-is-sorted\", \"difficulty\": \"Medium\", \"translatedTitle\": null}, {\"title\": \"Two Sum III - Data structure design\", \"titleSlug\": \"two-sum-iii-data-structure-design\", \"difficulty\": \"Easy\", \"translatedTitle\": null}, {\"title\": \"Subarray Sum Equals K\", \"titleSlug\": \"subarray-sum-equals-k\", \"difficulty\": \"Medium\", \"translatedTitle\": null}, {\"title\": \"Two Sum IV - Input is a BST\", \"titleSlug\": 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null}, {\"title\": \"Largest Positive Integer That Exists With Its Negative\", \"titleSlug\": \"largest-positive-integer-that-exists-with-its-negative\", \"difficulty\": \"Easy\", \"translatedTitle\": null}, {\"title\": \"Number of Distinct Averages\", \"titleSlug\": \"number-of-distinct-averages\", \"difficulty\": \"Easy\", \"translatedTitle\": null}, {\"title\": \"Count Pairs Whose Sum is Less than Target\", \"titleSlug\": \"count-pairs-whose-sum-is-less-than-target\", \"difficulty\": \"Easy\", \"translatedTitle\": null}]", "exampleTestcases": "[2,7,11,15]\n9\n[3,2,4]\n6\n[3,3]\n6", "categoryTitle": "Algorithms", "contributors": [], "topicTags": [ { "name": "Array", "slug": "array", "translatedName": null, "__typename": "TopicTagNode" }, { "name": "Hash Table", "slug": "hash-table", "translatedName": null, "__typename": "TopicTagNode" } ], "companyTagStats": null, "codeSnippets": [ { "lang": "C++", "langSlug": "cpp", "code": "class Solution {\npublic:\n vector twoSum(vector& nums, int target) {\n \n }\n};", "__typename": "CodeSnippetNode" }, { "lang": "Java", "langSlug": "java", "code": "class Solution {\n public int[] twoSum(int[] nums, int target) {\n \n }\n}", "__typename": "CodeSnippetNode" }, { "lang": "Python", "langSlug": "python", "code": "class Solution(object):\n def twoSum(self, nums, target):\n \"\"\"\n :type nums: List[int]\n :type target: int\n :rtype: List[int]\n \"\"\"\n ", "__typename": "CodeSnippetNode" }, { "lang": "Python3", "langSlug": "python3", "code": "class Solution:\n def twoSum(self, nums: List[int], target: int) -> List[int]:\n ", "__typename": "CodeSnippetNode" }, { "lang": "C", "langSlug": "c", "code": "/**\n * Note: The returned array must be malloced, assume caller calls free().\n */\nint* twoSum(int* nums, int numsSize, int target, int* returnSize) {\n \n}", "__typename": "CodeSnippetNode" }, { "lang": "C#", "langSlug": "csharp", "code": "public class Solution {\n public int[] TwoSum(int[] nums, int target) {\n \n }\n}", 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"lang": "Dart", "langSlug": "dart", "code": "class Solution {\n List twoSum(List nums, int target) {\n \n }\n}", "__typename": "CodeSnippetNode" }, { "lang": "Go", "langSlug": "golang", "code": "func twoSum(nums []int, target int) []int {\n \n}", "__typename": "CodeSnippetNode" }, { "lang": "Ruby", "langSlug": "ruby", "code": "# @param {Integer[]} nums\n# @param {Integer} target\n# @return {Integer[]}\ndef two_sum(nums, target)\n \nend", "__typename": "CodeSnippetNode" }, { "lang": "Scala", "langSlug": "scala", "code": "object Solution {\n def twoSum(nums: Array[Int], target: Int): Array[Int] = {\n \n }\n}", "__typename": "CodeSnippetNode" }, { "lang": "Rust", "langSlug": "rust", "code": "impl Solution {\n pub fn two_sum(nums: Vec, target: i32) -> Vec {\n \n }\n}", "__typename": "CodeSnippetNode" }, { "lang": "Racket", "langSlug": "racket", "code": "(define/contract (two-sum nums target)\n (-> (listof exact-integer?) exact-integer? 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It is from these brute force solutions that you can come up with optimizations.", "So, if we fix one of the numbers, say x, we have to scan the entire array to find the next number y which is value - x where value is the input parameter. Can we change our array somehow so that this search becomes faster?", "The second train of thought is, without changing the array, can we use additional space somehow? 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Compiled with clang 11 using the latest C++ 20 standard.

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Your code is compiled with level two optimization (-O2). AddressSanitizer is also enabled to help detect out-of-bounds and use-after-free bugs.

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Most standard library headers are already included automatically for your convenience.

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OpenJDK 17. Java 8 features such as lambda expressions and stream API can be used.

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Most standard library headers are already included automatically for your convenience.

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Python 2.7.12.

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Most libraries are already imported automatically for your convenience, such as array, bisect, collections. If you need more libraries, you can import it yourself.

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For Map/TreeMap data structure, you may use sortedcontainers library.

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Note that Python 2.7 will not be maintained past 2020. For the latest Python, please choose Python3 instead.

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Compiled with gcc 8.2 using the gnu11 standard.

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Most standard library headers are already included automatically for your convenience.

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1. Adding an item to a hash.\\r\\n

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2. Looking up an item in a hash:\\r\\n

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\\r\\n

\\r\\n\\r\\n

3. Deleting an item in a hash:\\r\\n

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\\r\\n

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C# 10 with .NET 6 runtime

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Node.js 16.13.2.

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Ruby 3.1

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Some common data structure implementations are provided in the Algorithms module: https://www.rubydoc.info/github/kanwei/algorithms/Algorithms

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Go 1.21

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Python 3.10.

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Scala 2.13.7.

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Kotlin 1.9.0.

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Rust 1.58.1

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PHP 8.1.

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With bcmath module

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TypeScript 5.1.6, Node.js 16.13.2.

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Dart 2.17.3

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