搜索算法

1.顺序搜索

function sequentialSearch(item){    for(var i=0; i<arr.length; i++){        if(arr[i] === item){            return i;        }    }    return -1;}

2.二分搜索

function binarySearch(item){    arr.sort();    var start = 0,        end = arr.length-1,        mid, element;    while(start <= end){        mid = Math.floor((start+end)/2);        element = arr[mid];        if(item < element){            end = mid;        }else if(item > element){            start = mid;        }else{            return mid;        }    }    return -1;}