Create 1423-maximum-points-you-can-obtain-from-cards.js

Author: aadil42

javascript/1423-maximum-points-you-can-obtain-from-cards.js

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+/**
+ * Greedy | Sliding Window | PrefixSum 
+ * Time O(n) | Space O(1)
+ * https://leetcode.com/problems/maximum-points-you-can-obtain-from-cards/
+ * @param {number[]} cardPoints
+ * @param {number} k
+ * @return {number}
+ */
+var maxScore = function(cardPoints, k) {
+    
+    const total = cardPoints.reduce((acc, curr) => acc+curr, 0);
+    let currTotal = cardPoints.slice(0, cardPoints.length - k).reduce((acc, curr) => acc+curr, 0);
+    let max = total - currTotal;
+    
+    let left = 0;
+    let right = cardPoints.length - k - 1; // -1 because the array is 0 indexed.
+
+    while(right < cardPoints.length) {
+        currTotal -= cardPoints[left];
+        left++;
+        right++;
+        if(right < cardPoints.length) {
+            currTotal += cardPoints[right];
+            max = Math.max(max, total - currTotal);
+        }
+    }
+
+    return max;
+};