實現二維數組順時針旋轉的功能

用GO實現二維數組的順時針旋轉，總體思想為，確定好正方形二維數組的邊界，從邊開始旋轉，轉完整個邊界之后把二維數組向內縮小一個邊界，找到邊界，繼續旋轉(交換)....

例如：

{ 1,  2,  3,  4}

{ 5,  6,  7,  8}

{ 9,10,11,12}

{13,14,15,16}

旋轉后:

{13,  9,  5,  1}

{14,10,  6,  2}

{15,11,  7,  3}

{16,12,  8,  4}

 

package algorithm

func rotateSquare(arr *[][]int) {
    topLeftRow := 0
    topLeftCol := 0
    lowRightRow := len(*arr) - 1
    lowRightCol := len((*arr)[0]) - 1
    for ; topLeftRow <= lowRightRow && topLeftCol <= lowRightCol; {
        rotateEdge(arr, topLeftRow, topLeftCol, lowRightRow, lowRightCol)
        topLeftRow++
        topLeftCol++
        lowRightRow--
        lowRightCol--
    }
}

func rotateEdge(arr *[][]int, topLeftRow, topLeftCol, lowRightRow, lowRightCol int) {
    times := lowRightCol - topLeftCol
    for i := 0; i < times; i++ {
        origin := (*arr)[topLeftRow][topLeftCol+i]
        (*arr)[topLeftRow][topLeftCol+i] = (*arr)[lowRightRow-i][topLeftCol]
        (*arr)[lowRightRow-i][topLeftCol] = (*arr)[lowRightRow][lowRightCol-i]
        (*arr)[lowRightRow][lowRightCol-i] = (*arr)[topLeftRow+i][lowRightCol]
        (*arr)[topLeftRow+i][lowRightCol] = origin
    }
}

測試代碼為

package algorithm

import (
    "testing"
    "fmt"
)

func Test_rotateSquare(t *testing.T) {
    arr := [][]int{
        {1, 2, 3, 4},
        {5, 6, 7, 8},
        {9, 10, 11, 12},
        {13, 14, 15, 16},
    }
    rotateSquare(&arr)
    fmt.Println(arr)
}