二叉树

function getIndex(arr,val){
    var min = 0,max=arr.length-1,mid;
    while(min<=max){
        mid = (max+min)/2;
        if(val>arr[mid]){
            min = mid+1;
        }else if(val<arr[mid]){
            max = mid-1;
        }else{
            return mid;
        }
    }
    return min;
}