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Given an array of integers nums and an integer target, return indices of the two numbers such that they add up to target.You may assume that each input would have exactly one solution, and you may not use the same element twice.You can return the answer in any order. Example 1:Input: nums = [2,7,11,15], target = 9Output: [0,1]Explanation: Because nums[0] + nums[1] == 9, we return [0, 1].Example 2:Input: nums = [3,2,4], target = 6Output: [1,2]Example 3:Input: nums = [3,3], target = 6Output: [0,1] Constraints:2 <= nums.length <= 104-109 <= nums[i] <= 109-109 <= target <= 109Only one valid answer exists.

Question

Given an array of integers nums and an integer target, return indices of the two numbers such that they add up to target.You may assume that each input would have exactly one solution, and you may not use the same element twice.You can return the answer in any order. Example 1:Input: nums = [2,7,11,15], target = 9Output: [0,1]Explanation: Because nums[0] + nums[1] == 9, we return [0, 1].Example 2:Input: nums = [3,2,4], target = 6Output: [1,2]Example 3:Input: nums = [3,3], target = 6Output: [0,1] Constraints:2 <= nums.length <= 104-109 <= nums[i] <= 109-109 <= target <= 109Only one valid answer exists.

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Solution

This problem can be solved using a hash map (also known as a dictionary in Python). Here is a step-by-step solution:

  1. Initialize an empty hash map.
  2. Loop through the array, for each element do the following:
    • Check if the difference between the target and the current element exists in the hash map.
    • If it exists, return the index of the current element and the value from the hash map (which is the index of the other element).
    • If it doesn't exist, add the current element and its index to the hash map.
  3. Continue this process until you find a pair of elements that add up to the target.

Here is the Python code for the above steps:

def twoSum(nums, target):
    num_map = {}
    for i, num in enumerate(nums):
        complement = target - num
        if complement in num_map:
            return [num_map[complement], i]
        num_map[num] = i

This function takes an array of integers (nums) and a target integer (target) as input, and returns the indices of the two numbers in the array that add up to the target. The time complexity of this solution is O(n), where n is the length of the input array, because we traverse the list containing n elements only once. Each look up in the table costs only O(1) time.

This problem has been solved

Similar Questions

1. Two SumEasy53.1K1.8KCompaniesGiven an array of integers nums and an integer target, return indices of the two numbers such that they add up to target.You may assume that each input would have exactly one solution, and you may not use the same element twice.You can return the answer in any order. Example 1:Input: nums = [2,7,11,15], target = 9Output: [0,1]Explanation: Because nums[0] + nums[1] == 9, we return [0, 1].Example 2:Input: nums = [3,2,4], target = 6Output: [1,2]Example 3:Input: nums = [3,3], target = 6Output: [0,1] Constraints:2 <= nums.length <= 104

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

Given a sorted array of distinct integers and a target value, return the index if the target is found. If not, return the index where it would be if it were inserted in order.You must write an algorithm with O(log n) runtime complexity. Example 1:Input: nums = [1,3,5,6], target = 5Output: 2Example 2:Input: nums = [1,3,5,6], target = 2Output: 1Example 3:Input: nums = [1,3,5,6], target = 7Output: 4 Constraints:1 <= nums.length <= 104-104 <= nums[i] <= 104nums contains distinct values sorted in ascending order.-104 <= target <= 104

Given an array of integers nums sorted in non-decreasing order, find the starting and ending position of a given target value.If target is not found in the array, return [-1, -1].You must write an algorithm with O(log n) runtime complexity. Example 1:Input: nums = [5,7,7,8,8,10], target = 8Output: [3,4]Example 2:Input: nums = [5,7,7,8,8,10], target = 6Output: [-1,-1]Example 3:Input: nums = [], target = 0Output: [-1,-1] Constraints:0 <= nums.length <= 105-109 <= nums[i] <= 109nums is a non-decreasing array.-109 <= target <= 109

Write a Python class to find a pair of elements (indices of the two numbers) from a given array whose sum equals a specific target number.Note: There will be one solution for each input and do not use the same element twice.Sample Test CasesTest Case 1:Expected Output:Enter·comma-separated·numbers:·2,5,1,5,6,0Enter·target·value:·10index1=1,·index2=3Test Case 2:Expected Output:Enter·comma-separated·numbers:·3,4,5,6,2,9Enter·target·value:·9index1=0,·index2=3Test Case 3:Expected Output:Enter·comma-separated·numbers:·9,8,1,4,5Enter·target·value:·4No·valid·indices·found·for·the·target·value.

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