diff --git a/contents/flood_fill/code/javascript/flood_fill.js b/contents/flood_fill/code/javascript/flood_fill.js new file mode 100644 index 000000000..0fcb85e46 --- /dev/null +++ b/contents/flood_fill/code/javascript/flood_fill.js @@ -0,0 +1,96 @@ + +function isInBounds(canvas, x, y) { + return (x >= 0) && (x < canvas[0].length) && (y >= 0) && (y < canvas.length) +} + +function findNeighbors(canvas, x, y, oldColor) { + const allNeighbors = [ + [x, y - 1], // North + [x + 1, y], // East + [x, y + 1], // South + [x - 1, y] // West + ] + + return allNeighbors + .filter(loc => isInBounds(canvas, ...loc)) + .filter(loc => canvas[loc[1]][loc[0]] == oldColor) +} + +function stackFill(canvas, x, y, oldColor, newColor) { + const stack = [ + [x, y] + ] + + while (stack.length > 0) { + const [x, y] = stack.pop() + canvas[y][x] = newColor + + for(const n of findNeighbors(canvas, x, y, oldColor)) + stack.push(n) + } +} + +function queueFill(canvas, x, y, oldColor, newColor) { + const queue = [ + [x, y] + ] + + while (queue.length > 0) { + const [x, y] = queue.shift() + canvas[y][x] = newColor + + for (const n of findNeighbors(canvas, x, y, oldColor)) { + // Color neighbor pixel before enqueuing to prevent + // it from being colored multiple times + canvas[n[1]][n[0]] = newColor + queue.push(n) + } + } +} + +function recursiveFill(canvas, x, y, oldColor, newColor) { + canvas[y][x] = newColor + + for(const n of findNeighbors(canvas, x, y, oldColor)) + recursiveFill(canvas, ...n, oldColor, newColor) +} + +function copyGrid(canvas) { + return canvas.map(row => row.map(v => v)) +} + +function compareGrids(canvas1, canvas2) { + return canvas1.map((row, y) => { + return row.every((val, x) => canvas1[y][x] === canvas2[y][x]) + }).every(x => x) +} + +let orignal = [ + [0, 0, 0, 0, 0], + [0, 0, 0, 0, 0], + [1, 1, 1, 1, 1], + [0, 0, 0, 0, 0], + [0, 0, 0, 0, 0] +] + +let solutionGrid = [ + [1, 1, 1, 1, 1], + [1, 1, 1, 1, 1], + [1, 1, 1, 1, 1], + [0, 0, 0, 0, 0], + [0, 0, 0, 0, 0], +] + +let startLoc = [3, 1] + +let canvas = copyGrid(orignal) +recursiveFill(canvas, ...startLoc, 0, 1) +console.log(`Recursive Fill: ${compareGrids(canvas, solutionGrid)}`) + +canvas = copyGrid(orignal) +stackFill(canvas, ...startLoc, 0, 1) +console.log(`Stackfill: ${compareGrids(canvas, solutionGrid)}`) + +canvas = copyGrid(orignal) +queueFill(canvas, ...startLoc, 0, 1) +console.log(`Queuefill: ${compareGrids(canvas, solutionGrid)}`) diff --git a/contents/flood_fill/flood_fill.md b/contents/flood_fill/flood_fill.md index 836f86897..9b2f0903a 100644 --- a/contents/flood_fill/flood_fill.md +++ b/contents/flood_fill/flood_fill.md @@ -90,6 +90,8 @@ In code, this might look like this: [import:37-55, lang:"julia"](code/julia/flood_fill.jl) {% sample lang="c" %} [import:34-52, lang:"c"](code/c/flood_fill.c) +{% sample lang="js" %} +[import:6-17, lang:"javascript"](code/javascript/flood_fill.js) {% endmethod %} @@ -106,15 +108,8 @@ In code, it might look like this: [import:106-118, lang:"julia"](code/julia/flood_fill.jl) {% sample lang="c" %} [import:180-195, lang:"c"](code/c/flood_fill.c) -{% endmethod %} - -All code snippets for this chapter rely on an exterior `color` function, defined as - -{% method %} -{% sample lang="jl" %} -[import:23-35, lang:"julia"](code/julia/flood_fill.jl) -{% sample lang="c" %} -[import:28-32, lang:"c"](code/c/flood_fill.c) +{% sample lang="js" %} +[import:51-56, lang:"javascript"](code/javascript/flood_fill.js) {% endmethod %} The above code continues recursing through available neighbors as long as neighbors exist, and this should work so long as we are adding the correct set of neighbors. @@ -126,6 +121,8 @@ Additionally, it is possible to do the same type of traversal by managing a stac [import:57-77, lang:"julia"](code/julia/flood_fill.jl) {% sample lang="c" %} [import:85-108, lang:"c"](code/c/flood_fill.c) +{% sample lang="js" %} +[import:19-31, lang:"javascript"](code/javascript/flood_fill.js) {% endmethod %} This is ultimately the same method of traversal as before; however, because we are managing our own data structure, there are a few distinct differences: @@ -165,6 +162,8 @@ The code would look something like this: [import:80-104, lang:"julia"](code/julia/flood_fill.jl) {% sample lang="c" %} [import:155-178, lang:"c"](code/c/flood_fill.c) +{% sample lang="js" %} +[import:33-49, lang:"javascript"](code/javascript/flood_fill.js) {% endmethod %} Now, there is a small trick in this code that must be considered to make sure it runs optimally. @@ -243,6 +242,8 @@ After, we will fill in the left-hand side of the array to be all ones by choosin [import, lang:"julia"](code/julia/flood_fill.jl) {% sample lang="c" %} [import, lang:"c"](code/c/flood_fill.c) +{% sample lang="js" %} +[import, lang:"javascript"](code/javascript/flood_fill.js) {% endmethod %}