2d:null 2e:["$","title",null,{"children":"Prim’s Algorithm Flood | Samson Stannus | Observable"}] 33:T474,animation = { const fills = new Array(cellWidth * cellHeight); const width = cellWidth * (cellSize + cellSpacing) + cellSpacing; const height = cellHeight * (cellSize + cellSpacing) + cellSpacing; const context = DOM.context2d(width, height); // context.canvas.style.imageRendering = "pixelated"; context.fillStyle = "#fff"; context.fillRect(0, 0, width, height); context.fillStyle = "#fff"; fillCells(context); for (let n, l = 0, frontier = [0]; n = frontier.length; ++l) { let frontier1 = []; context.fillStyle = sinebow(l / 2000); for (let i = 0, i0, i1; i < n; ++i) { fillCell(context, i0 = frontier[i]); if (cells[i0] & E && !fills[i1 = i0 + 1]) fillEast(context, i0), fills[i1] = frontier1.push(i1); if (cells[i0] & W && !fills[i1 = i0 - 1]) fillEast(context, i1), fills[i1] = frontier1.push(i1); if (cells[i0] & S && !fills[i1 = i0 + cellWidth]) fillSouth(context, i0), fills[i1] = frontier1.push(i1); if (cells[i0] & N && !fills[i1 = i0 - cellWidth]) fillSouth(context, i1), fills[i1] = frontier1.push(i1); } frontier = frontier1; yield context.canvas; } }34:T4e5,function generate(cellWidth, cellHeight) { const heap = new Queue(); const cells = new Uint8Array(cellWidth * cellHeight); let edge; heap.push({index: 0, direction: N}, Math.random()); heap.push({index: 0, direction: E}, Math.random()); while (edge = heap.pop()) { let i0 = edge.index, i1; let d0 = edge.direction, d1; let x0 = i0 % cellWidth, x1; let y0 = i0 / cellWidth | 0, y1; if (d0 === N) i1 = i0 - cellWidth, x1 = x0, y1 = y0 - 1, d1 = S; else if (d0 === S) i1 = i0 + cellWidth, x1 = x0, y1 = y0 + 1, d1 = N; else if (d0 === W) i1 = i0 - 1, x1 = x0 - 1, y1 = y0, d1 = E; else i1 = i0 + 1, x1 = x0 + 1, y1 = y0, d1 = W; if (cells[i1] === 0) { cells[i0] |= d0, cells[i1] |= d1; if (y1 > 0 && cells[i1 - cellWidth] === 0) { heap.push({index: i1, direction: N}, Math.random()); } if (y1 < cellHeight - 1 && cells[i1 + cellWidth] === 0) { heap.push({index: i1, direction: S}, Math.random()); } if (x1 > 0 && cells[i1 - 1] === 0) { heap.push({index: i1, direction: W}, Math.random()); } if (x1 < cellWidth - 1 && cells[i1 + 1] === 0) { heap.push({index: i1, direction: E}, Math.random()); } } } return cells; }35:[] 31:{"id":"4865e7eb26f05878","slug":"prims-algorithm-flood","title":"Prim’s Algorithm Flood","thumbnail":"2812476cf4029eb5bff48cec0c7bd21277ec32cd92bc75466961cbf2287f43e7","access_level":"public","create_time":"$D2019-04-21T21:12:37.506Z","update_time":"$D2019-04-22T00:36:11.935Z","view_time":null,"first_public_time":"$D2019-04-21T21:15:54.947Z","has_unpublished_edits":null,"fork":{"id":"b9dceb66104c9915","slug":"prims-algorithm-flood","title":"Prim’s Algorithm Flood","owner":{"id":"8c2e47252fd4995c","login":"mbostock","name":"Mike Bostock"}},"stars":0,"starred":false,"owner":{"type":"team","id":"cdbe434e68ec4e09","login":"samsonstannus","name":"Samson Stannus","avatar_url":"https://avatars-next.observableusercontent.com/0c2448d6294bc200663a7913bc2d12785b8fa0646a33dbe8a980fa2c5fdd09e4","tier":"starter_2024"},"version":191,"publish_version":191,"role":null,"authored":false,"authors":[{"type":"individual","id":"2149a00a0df35768","login":"samsonstannus","name":"Samson Stannus","avatar_url":"https://avatars-next.observableusercontent.com/0c2448d6294bc200663a7913bc2d12785b8fa0646a33dbe8a980fa2c5fdd09e4","tier":null}],"members":[{"type":"individual","id":"2149a00a0df35768","login":"samsonstannus","name":"Samson Stannus","avatar_url":"https://avatars-next.observableusercontent.com/0c2448d6294bc200663a7913bc2d12785b8fa0646a33dbe8a980fa2c5fdd09e4","tier":null,"role":"editor"}],"comments":[],"custom_thumbnail":false,"trashed":false,"lapsed":null,"subscribed":null,"forks":0,"collection":null,"type":"notebook","body":{"title":"Prim’s Algorithm Flood","cells":[{"id":0,"value":"md`# Prim’s Algorithm Flood\n\nThis maze is generated using Prim’s algorithm and then flooded with color. Hue encodes Manhattan distance from the starting cell. (This is not an optimal visual encoding, but it suffices and is pretty.)`","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":125,"value":"viewof replay = html`