算法 practice Day 1

var quickSort = function(arr) {
	if(arr.length <= 1) return arr;
	var middleIndex = Math.floor(arr.length /2);
	var middleValue = arr.splice(middleIndex,1);
	var right = [];
	var left = [];
	for(var i = 0;i<arr.length;i++){
		arr[i] < middleValue ? left.push(arr[i]) : right.push(arr[i]);
	}
	return quickSort(left).concat(middleValue,quickSort(right))
}

function insertSort(arr) {
	var len = arr.length;
	for (var i = 1; i < len; i++) {
		var currentVal = arr[i];
		var pre = i - 1;
		while (pre >= 0 && arr[pre] > currentVal) {
			arr[pre + 1] = arr[pre];
			pre--;
		}
		arr[pre + 1] = currentVal;
	}
	return arr;
}