/**
 * Time O(ROWS * COLS) | Space O(1)
 * https://leetcode.com/problems/rotate-image/
 * @param {number[][]} matrix
 * @return {void} Do not return anything, modify matrix in-place instead.
 */
var rotate = (matrix) => {
    transpose(matrix); /* Time O(ROWS * COLS) */
    reflect(matrix); /* Time O(ROWS * COLS) */
};

var transpose = (matrix) => {
    const rows = matrix.length;

    for (let row = 0; row < rows; row++) {
        /* Time O(ROWS) */
        for (let col = row + 1; col < rows; col++) {
            /* Time O(COLS) */
            swap1(matrix, row, col);
        }
    }
};

var swap1 = (matrix, row, col) =>
    ([matrix[row][col], matrix[col][row]] = [
        matrix[col][row],
        matrix[row][col],
    ]);

var reflect = (matrix) => {
    const rows = matrix.length;

    for (let row = 0; row < rows; row++) {
        /* Time O(ROWS) */
        for (let col = 0; col < rows / 2; col++) {
            /* Time O(COLS) */
            const reflection = rows - col - 1;

            swap2(matrix, row, col, reflection);
        }
    }
};

var swap2 = (matrix, row, col, reflection) =>
    ([matrix[row][col], matrix[row][reflection]] = [
        matrix[row][reflection],
        matrix[row][col],
    ]);

/**
 * Time O(ROWS * COLS) | Space O(1)
 * https://leetcode.com/problems/rotate-image/
 * @param {number[][]} matrix
 * @return {void} Do not return anything, modify matrix in-place instead.
 */
var rotate = (matrix) => {
    reverse(matrix); /* Time O(ROWS) */
    transpose(matrix); /* Time O(ROWS * COLS) */
};

var reverse = (matrix) => matrix.reverse();

var transpose = (matrix) => {
    const rows = matrix.length;

    for (let row = 0; row < rows; row++) {
        /* Time O(ROWS) */
        for (let col = 0; col < row; col++) {
            /* Time O(COLS) */
            swap(matrix, row, col);
        }
    }
};

var swap = (matrix, row, col) =>
    ([matrix[row][col], matrix[col][row]] = [
        matrix[col][row],
        matrix[row][col],
    ]);