Leetcode: Two Sum Problem Explained (For Beginners)

[shinoX3N9]

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

Example:

• nums = [2, 7, 11, 15], target = 9
• Output: [0, 1]
• Explanation: 2 + 7 = 9 (indices 0 and 1)

Simple Solution (Python):

def twoSum(nums, target):
    for i in range(len(nums)):
        for j in range(i+1, len(nums)):
            if nums[i] + nums[j] == target:
                return [i, j]

# Example usage:
nums = [2, 7, 11, 15]
target = 9
print(twoSum(nums, target))  # Output: [0, 1]

Explanation for Dummies:

• Look at each number in the list.
• For every number, check every other number after it to find a pair that adds up to your target number.
• If you find them, return their positions (indices) in the list.

Feel free to comment with your questions or share other solutions!

 

[jisoo69]

use hash map para effiecient