package main

import (
	"fmt"
)

func main() {
	matrix := [][]int{{1, 2, 3}, {4, 5, 6}, {7, 8, 9}}
	fmt.Println(matrix)
	rotate(matrix)
	fmt.Println(matrix)
}

func rotate(matrix [][]int) {
	m := len(matrix)
	tmp := 0

	for i := 0; i < m/2; i++ {
		for j := i; j < m-1-i; j++ {
			tmp = matrix[i][j]
			matrix[i][j] = matrix[m-1-j][i]
			matrix[m-1-j][i] = matrix[m-1-i][m-1-j]
			matrix[m-1-i][m-1-j] = matrix[j][m-1-i]
			matrix[j][m-1-i] = tmp
		}
	}
}