[algorithm] sword finger offer2 golang interview question 6: sum of two numbers in the sorting array

[ Algorithm ] The finger of the sword offer2 golang Interview questions 6： Sort the sum of two numbers in the array

subject 1:

Given a has been according to Ascending order Array of integers for numbers , Please find out two numbers from the array, and the sum of them is equal to the target number target .

Functions should be length based 2 Returns the subscript values of the two numbers in the form of an array of integers .numbers The subscript from 0 Start counting , So the answer array should satisfy 0 <= answer[0] < answer[1] < numbers.length .

Suppose that there is only one pair of qualified numbers in the array , At the same time, a number cannot be used twice .

Example 1：

Input ：numbers = [1,2,4,6,10], target = 8
Output ：[1,3]
explain ：2 And 6 The sum is equal to the number of targets 8 . therefore index1 = 1, index2 = 3 .
Example 2：

Input ：numbers = [2,3,4], target = 6
Output ：[0,2]
Example 3：

Input ：numbers = [-1,0], target = -1
Output ：[0,1]

Tips ：

2 <= numbers.length <= 3 * 104
-1000 <= numbers[i] <= 1000
numbers Press Increasing order array
-1000 <= target <= 1000
There is only one valid answer

source ： Power button （LeetCode）
link ：https://leetcode-cn.com/problems/kLl5u1
Copyright belongs to the network . For commercial reprint, please contact the official authority , Non-commercial reprint please indicate the source .

Ideas 1:

// Ideas 1:  Double pointer 
//left,right 
// If left plus right is less than target,left ++
// If left plus right is greater than target,right --
// Equal return  {left,right}

Code

func twoSum(numbers []int, target int) []int {
    
    // Ideas 1:  Double pointer 
    //left,right 
    // If left plus right is less than target,left ++
    // If left plus right is greater than target,right --
    // Equal return  {left,right}
    
    // Processing parameters 
    if len(numbers) < 2 {
    
        return nil 
    }

    // Double pointer 
    left,right := 0,len(numbers) - 1
    for left < right{
    
        tempTarget := numbers[left] + numbers[right]
        if tempTarget == target {
    
            return []int{
    left,right}
        }else if tempTarget < target {
    
            left ++
        }else if tempTarget > target {
    
            right --
        }
    }

    // Return empty if not found 
    return nil
}

test