二分法查找

随机产生15个不想等的[0,100]之间的随机数，对这15个数从小到大排序，然后应用二分法查找34是否在这15个随机数里边

function random(num) {
    var arr = []
    while(arr.length < num) {
        var num = Math.floor(Math.random()*100); //生成一个0-100的随机数
        if(arr.length === 0) {
            arr.push(num)
        } else {
            for(var i = 0;i<arr.length;i++) {
                if(arr.join(',').indexOf(num)<0){
                    arr.push(num)
                }
            }
        }
        
    }
    return arr
    
}
let newArray = random(15)

newArray.sort(function(a,b){
    return a-b
})
console.log(newArray)

function getNum(arr,num) {
    var len = arr.length,
    st = 0,
    end = len-1;
    while(st<=end){
        var mid = Math.floor((st+end)/2)
        if(num == arr[mid]) {
            return mid
        }else if(num> arr[mid]){
            st = mid+1
        } else {
            end = mid-1
        }
    }
    return arr
}
let cur = getNum(newArray,34)
if(cur instanceof Array) {
    console.log('无')
} else {
    console.log('找到了下表为'+ cur)
}