freecodecamp--freecodecamp/curriculum/challenges/english/blocks/daily-coding-challenges-javascript/6a1d9f98e819ed70a0e994db.md

id, title, challengeType, dashedName

id	title	challengeType	dashedName
6a1d9f98e819ed70a0e994db	Challenge 329: Bucket Fill	28	challenge-329

--description--

Given a 2D grid, a starting position ([row, col]), and a new value, replace the value at the starting position and all connected cells of the same value with the new value.

• Cells are connected if they are adjacent horizontally or vertically (not diagonally).

Return the updated grid.

--hints--

bucketFill([["R", "G"], ["R", "G"]], [0, 1], "B") should return [["R", "B"], ["R", "B"]].

assert.deepEqual(bucketFill([["R", "G"], ["R", "G"]], [0, 1], "B"), [["R", "B"], ["R", "B"]]);

bucketFill([["Y", "G", "G"], ["Y", "Y", "Y"], ["B", "Y", "R"]], [1, 2], "B") should return [["B", "G", "G"], ["B", "B", "B"], ["B", "B", "R"]].

assert.deepEqual(bucketFill([["Y", "G", "G"], ["Y", "Y", "Y"], ["B", "Y", "R"]], [1, 2], "B"), [["B", "G", "G"], ["B", "B", "B"], ["B", "B", "R"]]);

bucketFill([["O", "O", "P"], ["P", "O", "O"], ["P", "P", "O"]], [2, 0], "R") should return [["O", "O", "P"], ["R", "O", "O"], ["R", "R", "O"]].

assert.deepEqual(bucketFill([["O", "O", "P"], ["P", "O", "O"], ["P", "P", "O"]], [2, 0], "R"), [["O", "O", "P"], ["R", "O", "O"], ["R", "R", "O"]]);

bucketFill([["T", "T", "R", "T"], ["R", "T", "R", "T"], ["R", "T", "R", "T"], ["T", "T", "T", "T"]], [0, 3], "Y") should return [["Y", "Y", "R", "Y"], ["R", "Y", "R", "Y"], ["R", "Y", "R", "Y"], ["Y", "Y", "Y", "Y"]].

assert.deepEqual(bucketFill([["T", "T", "R", "T"], ["R", "T", "R", "T"], ["R", "T", "R", "T"], ["T", "T", "T", "T"]], [0, 3], "Y"), [["Y", "Y", "R", "Y"], ["R", "Y", "R", "Y"], ["R", "Y", "R", "Y"], ["Y", "Y", "Y", "Y"]]);

bucketFill([["G", "B", "G", "B"], ["R", "B", "B", "G"], ["B", "G", "B", "R"], ["B", "G", "G", "B"]], [2, 2], "G") should return [["G", "G", "G", "B"], ["R", "G", "G", "G"], ["B", "G", "G", "R"], ["B", "G", "G", "B"]].

assert.deepEqual(bucketFill([["G", "B", "G", "B"], ["R", "B", "B", "G"], ["B", "G", "B", "R"], ["B", "G", "G", "B"]], [2, 2], "G"), [["G", "G", "G", "B"], ["R", "G", "G", "G"], ["B", "G", "G", "R"], ["B", "G", "G", "B"]]);

--seed--

--seed-contents--

function bucketFill(grid, [row, col], newValue) {

  return grid;
}

--solutions--

function bucketFill(grid, [row, col], newValue) {
  const target = grid[row][col];
  if (target === newValue) return grid;

  function fill(r, c) {
    if (r < 0 || r >= grid.length) return;
    if (c < 0 || c >= grid[0].length) return;
    if (grid[r][c] !== target) return;

    grid[r][c] = newValue;
    fill(r - 1, c);
    fill(r + 1, c);
    fill(r, c - 1);
    fill(r, c + 1);
  }

  fill(row, col);
  return grid;
}