diff --git a/javascript/1463-cherry-pickup-ii.js b/javascript/1463-cherry-pickup-ii.js new file mode 100644 index 000000000..e668dd235 --- /dev/null +++ b/javascript/1463-cherry-pickup-ii.js @@ -0,0 +1,41 @@ +/** + * 2D-DP | Memoization + * Time O(n^3) | Space O(n^3); + * https://leetcode.com/problems/cherry-pickup-ii/ + * @param {number[][]} grid + * @return {number} + */ +var cherryPickup = function(grid) { + + const ROW = grid.length; + const COL = grid[0].length; + const cache = new Map(); + + const columnOutOfBound = (c) => { + if (c < 0) return true; + if (c === COL) return true; + return false; + } + + const dfs = (r1, c1, c2) => { + + const hash = `${r1}-${c1}-${c2}`; + if (cache.has(hash)) return cache.get(hash); + if (columnOutOfBound(c1) || columnOutOfBound(c2)) return 0; + if (r1 === ROW) return 0; + + const currTwoRobotSum = grid[r1][c1] + (c1 !== c2 && grid[r1][c2] || 0) + + let max = 0; + for (let i = c1-1; i < c1+2; i++) { + for (let j = c2-1; j < c2+2; j++) { + max = Math.max(max, currTwoRobotSum + dfs(r1+1, i, j)); + } + } + + cache.set(hash, max); + return max; + } + + return dfs(0,0, COL-1); +};