# 2022-05-17

## ​283. Move Zeroes​

### Description

Given an integer array `nums`, move all `0`'s to the end of it while maintaining the relative order of the non-zero elements.
Note that you must do this in-place without making a copy of the array.
Example 1:
Input: nums = [0,1,0,3,12]
Output: [1,3,12,0,0]
Example 2:
Input: nums = 
Output: 
Constraints:
• `1 <= nums.length <= 104`
• `-231 <= nums[i] <= 231 - 1`
Follow up: Could you minimize the total number of operations done?

### Solution

func moveZeroes(nums []int) {
for i, j := 0, 0; j < len(nums); {
if nums[j] != 0 {
nums[i], nums[j] = nums[j], nums[i]
i++
}
j++
}
}

## ​167. Two Sum II - Input Array Is Sorted​

### Description

Given a 1-indexed array of integers `numbers` that is already sorted in non-decreasing order, find two numbers such that they add up to a specific `target` number. Let these two numbers be `numbers[index1]` and `numbers[index2]` where `1 <= index1 < index2 <= numbers.length`.
Return the indices of the two numbers, `index1` and `index2`, added by one as an integer array `[index1, index2]` of length 2.
The tests are generated such that there is exactly one solution. You may not use the same element twice.
Your solution must use only constant extra space.
Example 1:
Input: numbers = [2,7,11,15], target = 9
Output: [1,2]
Explanation: The sum of 2 and 7 is 9. Therefore, index1 = 1, index2 = 2. We return [1, 2].
Example 2:
Input: numbers = [2,3,4], target = 6
Output: [1,3]
Explanation: The sum of 2 and 4 is 6. Therefore index1 = 1, index2 = 3. We return [1, 3].
Example 3:
Input: numbers = [-1,0], target = -1
Output: [1,2]
Explanation: The sum of -1 and 0 is -1. Therefore index1 = 1, index2 = 2. We return [1, 2].
Constraints:
• `2 <= numbers.length <= 3 * 104`
• `-1000 <= numbers[i] <= 1000`
• `numbers` is sorted in non-decreasing order.
• `-1000 <= target <= 1000`
• The tests are generated such that there is exactly one solution.

### Solution

#### Approach #0

func twoSum(numbers []int, target int) []int {
for i := 0; i < len(numbers); i++ {
for j := i + 1; j < len(numbers); j++ {
if numbers[i]+numbers[j] == target {
return []int{i + 1, j + 1}
}
}
}
return []int{}
}

#### Approach #1

func twoSum(numbers []int, target int) []int {
for i, j := 0, len(numbers)-1; i < j; {
sum := numbers[i] + numbers[j]
if sum == target {
return []int{i + 1, j + 1}
}
if sum > target {
j--
} else {
i++
}
}
return []int{}
}