归并排序(Merge Sort) 归并排序(Merge Sort) **归并排序(mergesort)的构思朴实而深刻,作为一个算法即古老又仍不失生命力。在排序算法的发展历史上,归并排序具有特殊的历史地位,它是第一个可以在最坏情况下依然保持O(nlogn)**运行时间的确定性排序算法。 无序向量的递归分解+有序向量的逐层合并(二...
functioncountInversions($arr){$temp=array_fill(0,count($arr),0);returnmergeSort($arr,$temp,0,count($arr)-1);}functionmergeSort(&$arr,&$temp,$left,$right){$inversions=0;if($left<$right){$mid=(int)(($left+$right)/2);$inversions+=mergeSort($arr,$temp,$left,$mid);$inversions+...
Comparable w) {11returnv.compareTo(w) < 0;12}1314publicstaticintinversionsNum(Comparable[] a) {15aux =newComparable[a.length];16sort(a, 0, a.length - 1);17return
Solution: importjava.io.*;importjava.util.*;importjava.text.*;importjava.math.*;importjava.util.regex.*;publicclassSolution{publicstaticlongcountInversions(int[]arr){returnmergeSort(arr,0,arr.length-1);}publicstaticlongmergeSort(int[]arr,intstart,intend){if(start==end)return0;longcount=0;in...
We sort the following datasets: is already sorted, so there are no inversions for us to correct. Thus, we print on a new line. We performed a total of swaps to correct inversions. 题目解析 核心就是Merge排序,注意在新建数组的时候直接赋值,append等会导致超时。就是用递归 每次都拿两个排序好的...
The way in which we'll divide will be motivated directly by merge sort where we recurs e separately on the left and the right half's of the array. We're gonna do the same thing here. To understand how much progress we can make purely using recursion let's classify the inversions of ...