Add solution #66

Author: JoshCrozier

README.md

@@ -10,6 +10,7 @@
 36|[Valid Sudoku](./0036-valid-sudoku.js)|Medium|
 43|[Multiply Strings](./0043-multiply-strings.js)|Medium|
 58|[Length of Last Word](./0058-length-of-last-word.js)|Easy|
+66|[Plus One](./0066-plus-one.js)|Easy|
 67|[Add Binary](./0067-add-binary.js)|Easy|
 151|[Reverse Words in a String](./0151-reverse-words-in-a-string.js)|Medium|
 226|[Invert Binary Tree](./0226-invert-binary-tree.js)|Easy|

solutions/0066-plus-one.js

@@ -0,0 +1,41 @@
+/**
+ * 66. Plus One
+ * https://leetcode.com/problems/plus-one/
+ * Difficulty: Easy
+ *
+ * Given a non-empty array of digits representing a non-negative integer,
+ * plus one to the integer.
+ *
+ * The digits are stored such that the most significant digit is at the
+ * head of the list, and each element in the array contain a single digit.
+ *
+ * You may assume the integer does not contain any leading zero,
+ * except the number 0 itself.
+ */
+
+/**
+ * @param {number[]} digits
+ * @return {number[]}
+ */
+var plusOne = function(digits) {
+  let i = digits.length - 1;
+  digits[i] += 1;
+  while (digits[i] > 9) {
+    digits[i--] = 0;
+    if (digits[i]) {
+      digits[i] += 1;
+    } else {
+      digits.unshift(1);
+    }
+  }
+  return digits;
+};
+
+// alternative one-liner that breaks the rules:
+/**
+ * @param {number[]} digits
+ * @return {number[]}
+ */
+var plusOne = function(digits) {
+  return String(BigInt(digits.join('')) + BigInt(1)).split('');
+};