Algorithms

wasmのチュートリアルを実施した際に見つけたやつ。 詳しくはこちら fn live_neighbor_count(&self, row: u32, column: u32) -> u8 { let mut count = 0; for delta_row in [self.height - 1, 0, 1].iter().cloned() { for delta_col in [self.width - 1, 0, 1].iter().cloned() { if delta_row == 0 && delta_col == 0 { continue; } let neighbor_row = (row + delta_row) % self.height; let neighbor_col = (column + delta_col) % self.width; let idx = self.get_index(neighbor_row, neighbor_col); count += self.cells[idx] as u8; } } count } パフォーマンス改良版はこれ。 （こっちはこの記事を参考） fn live_neighbor_count(&self, row: u32, column: u32) -> u8 { let mut count = 0; let north = if row == 0 { self.height - 1 } else { row - 1 }; let south = if row == self.height - 1 { 0 } else { row + 1 }; let west = if column == 0 { self.width - 1 } else { column - 1 }; let east = if column == self.width - 1 { 0 } else { column + 1 }; let nw = self.get_index(north, west); count += self.cells[nw] as u8; let n = self.get_index(north, column); count += self.cells[n] as u8; let ne = self.get_index(north, east); count += self.cells[ne] as u8; let w = self.get_index(row, west); count += self.cells[w] as u8; let e = self.get_index(row, east); count += self.cells[e] as u8; let sw = self.get_index(south, west); count += self.cells[sw] as u8; let s = self.get_index(south, column); count += self.cells[s] as u8; let se = self.get_index(south, east); count += self.cells[se] as u8; count }