归并排序和快速排序计时计算——谁更快？

今天复习了归并和快排，突然想计算一下他们的速度差别到底有多大～结果还是挺令人意外的，哈哈。

话不多说，看代码。

	let arr = [];
	for (let i = 0; i < 500000; i++) {
	    (((() * 1000)));
	}
	let start = new Date().getTime();
	
	/**
	 * 快速排序
	 */
	function quickSort(arr) {
	
	    if ( <= 1) {
	        return arr;
	    }
	
	    let mid =  >> 1;
	    let midValue = (mid, 1);
	    let left = [];
	    let right = [];
	
	    for (let i = 0; i < ; i++) {
	        if (arr[i] < midValue) {
	            (arr[i]);
	        } else {
	            (arr[i]);
	        }
	    }
	
	    return quickSort(left).concat(midValue, quickSort(right));
	}
	
	/**
	 * 归并排序
	 */
	function mergeSort(arr) {
	    function part(arr, left, right) {
	        if (left == right) {
	            return;
	        }
	        let mid = left + ((right - left) >> 1);
	
	        part(arr, left, mid);
	        part(arr, mid + 1, right);
	
	        let p1 = left;
	        let p2 = mid + 1;
	        let cache = [];
	        let i = 0;
	        while (p1 <= mid && p2 <= right) {
	            cache[i++] = arr[p1] < arr[p2] ? arr[p1++] : arr[p2++];
	        }
	
	        while (p1 <= mid) {
	            cache[i++] = arr[p1++];
	        }
	
	        while (p2 <= right) {
	            cache[i++] = arr[p2++];
	        }
	
	        for (let i = 0; i < ; i++) {
	            arr[left + i] = cache[i];
	        }
	
	        return arr;
	    }
	
	    return part(arr, 0,  - 1);
	}
	
	
	/**
	 * 验证
	 */
	(`结果：[${quickSort(arr)}]`);
	let end = new Date().getTime();
	(`用时：${end - start}毫秒`);