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..872b5e190 --- /dev/null +++ b/contents/flood_fill/code/javascript/flood_fill.js @@ -0,0 +1,101 @@ + +function isInBounds(canvas, x, y) { + return (x >= 0) && (x < canvas[0].length) && (y >= 0) && (y < canvas.length) +} + +function color(canvas, x, y, oldColor, newColor) { + if (isInBounds(canvas, x, y) && canvas[y][x] == oldColor) + canvas[y][x] = newColor +} + +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 currentLoc = stack.pop() + color(canvas, ...currentLoc, oldColor, newColor) + + for(const n of findNeighbors(canvas, ...currentLoc, oldColor)) + stack.push(n) + } +} + +function queueFill(canvas, x, y, oldColor, newColor) { + const queue = [ + [x, y] + ] + + while (queue.length > 0) { + const currentLoc = queue.shift() + color(canvas, ...currentLoc, oldColor, newColor) + + for (const n of findNeighbors(canvas, ...currentLoc, oldColor)) { + // Color neighbor pixel before enqueuing to prevent + // it from being colored multiple times + color(canvas, ...n, oldColor, newColor) + queue.push(n) + } + } +} + +function recursiveFill(canvas, x, y, oldColor, newColor) { + color(canvas, x, y, oldColor, 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..83dbe49a0 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:11-22, lang:"javascript"](code/javascript/flood_fill.js) {% endmethod %} @@ -106,6 +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) +{% sample lang="js" %} +[import:56-61, lang:"javascript"](code/javascript/flood_fill.js) {% endmethod %} All code snippets for this chapter rely on an exterior `color` function, defined as @@ -115,6 +119,8 @@ All code snippets for this chapter rely on an exterior `color` function, defined [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:6-9, 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 +132,8 @@ 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:24-36, 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 +173,8 @@ 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:38-54, 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 +253,8 @@ 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 %}