开发笔记:两数之和II输入有序数组二分查找

输入: numbers = [2, 7, 11, 15], target = 9
输出: [1,2]
解释: 2 与 7 之和等于目标数 9 。因此 index1 = 1, index2 = 2 。

func twoSum(_ numbers: [Int], _ target: Int) -> [Int] {
if numbers.count <= 0 {return []}
var low = 0
var high = numbers.count - 1
var resultArr = [Int]()
while low < high {
let sum = numbers[low] + numbers[high]
if sum == target {
//题目要求是第几个数据,但是数组下标为0开始
//numbers = [2, 7, 11, 15], target = 9 ,题目要求输出[1,2],而对应的数组为[0,1]
//所以low + 1,high + 1
resultArr.append(low + 1)
resultArr.append(high + 1)
return resultArr
} else if sum < target {
low += 1
} else {
high -= 1
}
}
return []
}