Binary Search

二元搜寻BigO(log n)

点我看GIF

let array1 = [1,3,5,7,9,11,13,15,17,19,21]function BinarySearch(array, n){    let min = 0    let max = array.length -1     while(array[min] <= array[max]){ //当array的前一项比后项小即成立        let middile = Math.floor((min + max) / 2) //为了对半middle 为中间的index        if(array[middile] > n){ //如果array[middle] > n 代表是在miidle的左半边,即把範围所小到当前middle的位置-1            max = middile - 1        }else if(array[middile] < n ){            min = middile + 1        }else{ //否则回传middle            console.log(`Found number index:${middile}`)            return middile        }    }return "Error"}BinarySearch(array1, 5) //Found number index:2