javascript 旋转方形矩阵90度

Posted 2021-05-03

// Rotate a matrix 90 degrees clockwise
// squares matrix
// [[1,2,3],
//  [4,5,6],
//  [7,8,9]]
 
// The result should be:
// [[7,4,1],
//  [8,5,2],
//  [9,6,3]]
 
function rotate(mat){
    const newMatrix = [];
    //this will create the number of array the matrix needs.
    for (let i=0; i < mat.length; i++) {
        newMatrix.push([]);
    }

    for (let i=0; i < mat.length; i++) {
        for (let j=0; j < mat.length; j++) {
            newMatrix[j][mat.length -1 -i] = mat[i][j];
            console.log(j, i, mat.length -1 -i, mat[i][j]);
        }
    }
    return newMatrix;
}
 
rotate(
    [[1,2,3],
    [4,5,6],
    [7,8,9]]
)