快速排序

快速排序的大致思想为取到中间位置的元素，其他元素和其一一比较，分列左右，然后左右再迭代使用以上步骤

	quickSort:function(arr) {
		if (arr.length <= 1) {return arr;}
		var pivotIndex = Math.floor(arr.length / 2);
		var pivot = arr.splice(pivotIndex, 1);
		var left = [];
		var right = [];
		for (var i = 0; i < arr.length; i++){
			if (arr[i] < pivot){
				left.push(arr[i]);
				}else{
				right.push(arr[i]);
				}
			}
		return quickSort(left).concat(pivot, quickSort(right));
	},
	quickSortObjArr:function(objArr,key) {
		if (objArr.length <= 1) {return objArr;}
		var pivotIndex = Math.floor(objArr.length / 2);
		//var pivot = objArr.splice(pivotIndex, 1);
		var pivot = objArr[pivotIndex];
		objArr.splice(pivotIndex, 1);	
		var left = [];
		var right = [];
		for (var i = 0; i < objArr.length; i++){		
			if (objArr[i][key] < pivot[key]){			
				left.push(objArr[i]);
				}else{
				right.push(objArr[i]);
				}
			}
		return quickSortObjArr(left,key).concat(pivot, quickSortObjArr(right,key));
	}