二分查找

二分查找主要是找出中间值，如果目标值在中间值左边，就将搜索区域移动到左边，如果在右边移动到右边

let list = [1,4,6,9,10,33,45,66,77]

func binarySearch(_ array:[Int], _ targat:Int) -> (Int,Bool){
    
    var left = 0, right = array.count-1, middel = 0
    while left <= right {
        middel = left + (right - left)/2
        
        if array[middel] == targat {
            return (middel,true)
        }
        
        if array[middel] < targat {
            left = middel+1
        }else{
            right = middel-1
        }
    }
    
    return (-1,false)
}

print(binarySearch(list, 78))

时间复杂度 O(log2n)