Golang算法问题之数组按指定规则排序的方法分析

package huawei
import (
    "fmt"
    "sort"
)
func Test09Base() {
    nums := [][]int{{1, 2, 3}, {2, 3, 4}, {2, 3, 1}, {1, 3, 1}}
    firstIndex := 2 //按第二列排序
    result := arraySort(nums, firstIndex-1)
    fmt.Println(result)
}
//按指定规则对nums进行排序(注：此firstIndex从0开始)
func arraySort(nums [][]int, firstIndex int) [][]int {
    //检查
    if len(nums) <= 1 {
        return nums
    }
    if firstIndex < 0 || firstIndex > len(nums[0])-1 {
        fmt.Println("Warning: Param firstIndex should between 0 and len(nums)-1. The original array is returned.")
        return nums
    }
    //排序
    mIntArray := &IntArray{nums, firstIndex}
    sort.Sort(mIntArray)
    return mIntArray.mArr
}
type IntArray struct {
    mArr       [][]int
    firstIndex int
}
//IntArray实现sort.Interface接口
func (arr *IntArray) Len() int {
    return len(arr.mArr)
}
func (arr *IntArray) Swap(i, j int) {
    arr.mArr[i], arr.mArr[j] = arr.mArr[j], arr.mArr[i]
}
func (arr *IntArray) Less(i, j int) bool {
    arr1 := arr.mArr[i]
    arr2 := arr.mArr[j]
    for index := arr.firstIndex; index < len(arr1); index++ {
        if arr1[index] < arr2[index] {
            return true
        } else if arr1[index] > arr2[index] {
            return false
        }
    }
    return i < j
}