Two Sum On Leetcode

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.

 

# Intuition

Solution :

like int nums[] = {1,2,3,4} 

    and target = 7;

select the first nums[0] and addition nums[1], nums[2] , num[3] nums[4]

addition->

only i index

    1+2 = 3

    1+3 = 4

    1+4 = 5

i+1 index 

    2+3 = 5

    2+4 = 6

i+2 index

    3+4 = 7 

and 

**one less second loop is driven**

hence condition is true 

then return and non premitive  in collect the **indices**

and return new int [] {i, j}

And no match target the handle the case

            *throw new IllegalArgumentException("no match found")*

 

# Approach

Brute force Approach 

 

# Complexity

- Time complexity:

    O(n2)

- Space complexity:

    O(1)

 

# Code

```

class Solution {

    public int[] twoSum(int[] nums, int target) {

        for (int i = 0; i < nums.length; i++) {

            for (int j = i + 1; j < nums.length; j++) {

                if (target == nums[i] + nums[j]) {

                    return new int[] { i, j };

                }

            }

        }

        // If no match is found, return an empty array.

        return new int[0];

    }

}

 


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