0054-spiral-matrix.ts

function spiralOrder(matrix: number[][]): number[] {
    const res: number[] = [];
    let left = 0;
    let right = matrix[0].length;
    let top = 0;
    let bottom = matrix.length;

    while (left < right && top < bottom) {
        // get every i in the top row
        for (let i = left; i < right; i++) {
            res.push(matrix[top][i]);
        }
        top += 1;

        // get every i in the right column
        for (let i = top; i < bottom; i++) {
            res.push(matrix[i][right - 1]);
        }
        right -= 1;

        if (!(left < right && top < bottom)) {
            break;
        }

        // get ever i in the bottom row
        for (let i = right - 1; i > left - 1; i--) {
            res.push(matrix[bottom - 1][i]);
        }
        bottom -= 1;

        // get evet i in the left column
        for (let i = bottom - 1; i > top - 1; i--) {
            res.push(matrix[i][left]);
        }
        left += 1;
    }

    return res;
}