import Foundation
func printMatrix(_ matrix: [[Int]]) {
for row in matrix {
print(row.map { String($0) }.joined(separator: " "))
}
}
/**
Rotates a square matrix 90 degrees to the left (counterclockwise).
Parameter matrix: The square matrix to rotate.
*/
func rotateMatrix90DegreesLeft(_ matrix: inout [[Int]]) {
let len = matrix.count
// Validate input: Ensure it's a square matrix
guard matrix.allSatisfy({ $0.count == len }) else {
fatalError("Input must be a square matrix.")
}
// Perform the rotation in-place
for layer in 0..<(len / 2) {
let first = layer
let last = len - 1 - layer
for i in first..<last {
let offset = i - first
// Save the top element
let top = matrix[first][i]
// Move right to top
matrix[first][i] = matrix[i][last]
// Move bottom to right
matrix[i][last] = matrix[last][last - offset]
// Move left to bottom
matrix[last][last - offset] = matrix[last - offset][first]
// Move top to left
matrix[last - offset][first] = top
}
}
}
var matrix = [
[1, 2, 3],
[4, 5, 6],
[7, 8, 9]
]
rotateMatrix90DegreesLeft(&matrix)
print("Matrix After 90° Left Rotation:")
printMatrix(matrix)
/*
run:
Matrix After 90° Left Rotation:
3 6 9
2 5 8
1 4 7
*/
