huangzj
55 lines
1.3 KiB
Go
55 lines
1.3 KiB
Go
/*
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* @Author : huangzj
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* @Time : 2020/8/19 11:44
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* @Description：这边提供一个递归的归并排序算法，非递归的理解成本比较高，并且还有多路归并排序，需要理解对应概念
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* 最坏时间复杂度O(nlogn) 最好时间复杂度O(logn) 空间复杂度O(n)
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*/
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package sort
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func MergeSort(list []int) {
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middle := len(list) / 2
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leftList := copyList(list, 0, middle)
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rightList := copyList(list, middle, len(list))
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if len(list) > 1 {
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MergeSort(leftList) //先对左边进行归并排序
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MergeSort(rightList) //再对右边进行归并排序
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mergeAll(list, leftList, rightList) //对左右排序的结果进行组合
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}
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}
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func copyList(list []int, start int, end int) []int {
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result := make([]int, 0)
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for i := start; i < end; i++ {
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result = append(result, list[i])
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}
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return result
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}
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func mergeAll(array []int, left []int, right []int) {
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l, r, i := 0, 0, 0 //左数组的下标、右数组的下标、组合数组的下标
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for l < len(left) && r < len(right) {
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if left[l] > right[r] {
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array[i] = right[r]
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i++
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r++
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} else {
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array[i] = left[l]
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i++
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l++
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}
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}
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for r < len(right) {
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array[i] = right[r]
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r++
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i++
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}
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for l < len(left) {
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array[i] = left[l]
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l++
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i++
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}
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}
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