Add solution #1463

Author: JoshCrozier

README.md

@@ -1,4 +1,4 @@
-# 1,314 LeetCode solutions in JavaScript
+# 1,315 LeetCode solutions in JavaScript
 
 [https://leetcodejavascript.com](https://leetcodejavascript.com)
 
@@ -1118,6 +1118,7 @@
 1460|[Make Two Arrays Equal by Reversing Sub-arrays](./solutions/1460-make-two-arrays-equal-by-reversing-sub-arrays.js)|Easy|
 1461|[Check If a String Contains All Binary Codes of Size K](./solutions/1461-check-if-a-string-contains-all-binary-codes-of-size-k.js)|Medium|
 1462|[Course Schedule IV](./solutions/1462-course-schedule-iv.js)|Medium|
+1463|[Cherry Pickup II](./solutions/1463-cherry-pickup-ii.js)|Hard|
 1464|[Maximum Product of Two Elements in an Array](./solutions/1464-maximum-product-of-two-elements-in-an-array.js)|Easy|
 1466|[Reorder Routes to Make All Paths Lead to the City Zero](./solutions/1466-reorder-routes-to-make-all-paths-lead-to-the-city-zero.js)|Medium|
 1470|[Shuffle the Array](./solutions/1470-shuffle-the-array.js)|Easy|

solutions/1463-cherry-pickup-ii.js

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+/**
+ * 1463. Cherry Pickup II
+ * https://leetcode.com/problems/cherry-pickup-ii/
+ * Difficulty: Hard
+ *
+ * You are given a rows x cols matrix grid representing a field of cherries where grid[i][j]
+ * represents the number of cherries that you can collect from the (i, j) cell.
+ *
+ * You have two robots that can collect cherries for you:
+ * - Robot #1 is located at the top-left corner (0, 0), and
+ * - Robot #2 is located at the top-right corner (0, cols - 1).
+ *
+ * Return the maximum number of cherries collection using both robots by following the rules below:
+ * - From a cell (i, j), robots can move to cell (i + 1, j - 1), (i + 1, j), or (i + 1, j + 1).
+ * - When any robot passes through a cell, It picks up all cherries, and the cell becomes an empty
+ *   cell.
+ * - When both robots stay in the same cell, only one takes the cherries.
+ * - Both robots cannot move outside of the grid at any moment.
+ * - Both robots should reach the bottom row in grid.
+ */
+
+/**
+ * @param {number[][]} grid
+ * @return {number}
+ */
+var cherryPickup = function(grid) {
+  const rows = grid.length;
+  const cols = grid[0].length;
+  const cache = new Array(rows).fill().map(() => {
+    return new Array(cols).fill().map(() => new Array(cols).fill(-1));
+  });
+
+  return Math.max(0, findMaxCherries(0, 0, cols - 1));
+
+  function findMaxCherries(row, col1, col2) {
+    if (row === rows || col1 < 0 || col1 >= cols || col2 < 0 || col2 >= cols) {
+      return -Infinity;
+    }
+    if (cache[row][col1][col2] !== -1) {
+      return cache[row][col1][col2];
+    }
+
+    const cherries = col1 === col2 ? grid[row][col1] : grid[row][col1] + grid[row][col2];
+
+    if (row === rows - 1) {
+      return cherries;
+    }
+
+    let maxCherries = -Infinity;
+    for (const nextCol1 of [col1 - 1, col1, col1 + 1]) {
+      for (const nextCol2 of [col2 - 1, col2, col2 + 1]) {
+        maxCherries = Math.max(maxCherries, findMaxCherries(row + 1, nextCol1, nextCol2));
+      }
+    }
+
+    cache[row][col1][col2] = cherries + maxCherries;
+    return cache[row][col1][col2];
+  }
+};