JS一些算法

楊輝三角：

var row = 10,
    arr = new Array();
for(var i=0;i<row;i++){
    var arrRow = [];
    for(var j=0;j<=i;j++){
        if(i == 0 || j ==0 || i==j){
            arrRow.push(1);
        }else{
            arrRow.push(arr[i-1][j-1] + arr[i-1][j]);
        }
    }
    console.log(arrRow.join(" ")+"\n");
    arr.push(arrRow);
}
row = null;

二分查找：

function twoSearch(arr, result){
    var mid = 0;
    var st = 0,end = arr.length-1;
    while(st <= end){
        mid = Math.floor((st + end)/2);
        if(result == arr[mid]){
            return mid;
        }else if(result < arr[mid]){
            end = mid - 1;
        }else{
            st = mid + 1;
        }
    }
    return -1;
}
var arr = [0,1,1,1,2,5,9,10,15,17,18,19,20,21,22,23,50,100];
console.log(twoSearch(arr, 2));

sort排序：

var arr = [222,1,55,10,22];
console.log(arr.sort(function(a, b){return a-b;}));

冒泡排序：

var arr = [222,66,55,10,22];
for(var i=0;i<arr.length;i++){
    for(var j=0;j<arr.length-i-1;j++){
        if(arr[j] > arr[j+1]){
            var cach = 0;
            cach = arr[j];
            arr[j] = arr[j+1];
            arr[j+1] = cach;
        }
    }
}
console.log(arr);

選擇排序：

var arr = [222,1,55,10,22];
var len = arr.length;
for(var i=0;i<len;i++){
    var maxIndex = 0;
    for(var j=1;j<len-i;j++){
        if(arr[j] > arr[maxIndex]){maxIndex = j;}
    }
    var cach = arr[maxIndex];
    arr[maxIndex] = arr[len-i-1];
    arr[len-i-1] = cach;
}
console.log(arr);
len = null;