--- id: 5900f4601000cf542c50ff72 title: 'Problem 244: Sliders' challengeType: 5 forumTopicId: 301891 dashedName: problem-244-sliders --- # --description-- You probably know the game Fifteen Puzzle. Here, instead of numbered tiles, we have seven red tiles and eight blue tiles. A move is denoted by the uppercase initial of the direction (Left, Right, Up, Down) in which the tile is slid, e.g. starting from configuration ($S$), by the sequence $LULUR$ we reach the configuration ($E$): ($S$) configuration S, ($E$) configuration E For each path, its checksum is calculated by (pseudocode): $$\begin{align} & \text{checksum} = 0 \\\\ & \text{checksum} = (\text{checksum} × 243 + m_1) \\; \text{mod} \\; 100\\,000\\,007 \\\\ & \text{checksum} = (\text{checksum} × 243 + m_2) \\; \text{mod} \\; 100\\,000\\,007 \\\\ & \ldots \\\\ & \text{checksum} = (\text{checksum} × 243 + m_n) \\; \text{mod} \\; 100\\,000\\,007 \end{align}$$ where $m_k$ is the ASCII value of the $k^{\text{th}}$ letter in the move sequence and the ASCII values for the moves are: $$\begin{array}{|c|c|} \hline L & 76 \\\\ \hline R & 82 \\\\ \hline U & 85 \\\\ \hline D & 68 \\\\ \hline \end{array}$$ For the sequence $LULUR$ given above, the checksum would be 19761398. Now, starting from configuration ($S$), find all shortest ways to reach configuration ($T$). ($S$) configuration S, ($T$) configuration T What is the sum of all checksums for the paths having the minimal length? # --hints-- `sliders()` should return `96356848`. ```js assert.strictEqual(sliders(), 96356848); ``` # --seed-- ## --seed-contents-- ```js function sliders() { return true; } sliders(); ``` # --solutions-- ```js // solution required ```