0733-flood-fill.js

/**
 * 733. Flood Fill
 * https://leetcode.com/problems/flood-fill/
 * Difficulty: Easy
 *
 * An image is represented by an m x n integer grid image where image[i][j] represents
 * the pixel value of the image.
 *
 * You are also given three integers sr, sc, and newColor. You should perform a flood
 * fill on the image starting from the pixel image[sr][sc].
 *
 * To perform a flood fill, consider the starting pixel, plus any pixels connected
 * 4-directionally to the starting pixel of the same color as the starting pixel,
 * plus any pixels connected 4-directionally to those pixels (also with the same color),
 * and so on. Replace the color of all of the aforementioned pixels with newColor.
 *
 * Return the modified image after performing the flood fill.
 */

/**
 * @param {number[][]} image
 * @param {number} sr
 * @param {number} sc
 * @param {number} newColor
 * @return {number[][]}
 */
var floodFill = function(image, sr, sc, newColor) {
  fill(image, sr, sc, image[sr][sc], newColor);
  return image;
};

function fill(image, x, y, initialColor, newColor) {
  if (image[x] && image[x][y] === initialColor && initialColor !== newColor) {
    image[x][y] = newColor;
    [[x - 1, y], [x + 1, y], [x, y - 1], [x, y + 1]]
      .forEach(([x, y]) => fill(image, x, y, initialColor, newColor));
  }
}