Add solution #65

Author: JoshCrozier

README.md

@@ -68,6 +68,7 @@
 60|[Permutation Sequence](./0060-permutation-sequence.js)|Hard|
 62|[Unique Paths](./0062-unique-paths.js)|Medium|
 64|[Minimum Path Sum](./0064-minimum-path-sum.js)|Medium|
+65|[Valid Number](./0065-valid-number.js)|Hard|
 66|[Plus One](./0066-plus-one.js)|Easy|
 67|[Add Binary](./0067-add-binary.js)|Easy|
 69|[Sqrt(x)](./0069-sqrtx.js)|Medium|

solutions/0065-valid-number.js

@@ -0,0 +1,33 @@
+/**
+ * 65. Valid Number
+ * https://leetcode.com/problems/valid-number/
+ * Difficulty: Hard
+ *
+ * Given a string s, return whether s is a valid number.
+ *
+ * For example, all the following are valid numbers: "2", "0089", "-0.1", "+3.14", "4.", "-.9",
+ * "2e10", "-90E3", "3e+7", "+6e-1", "53.5e93", "-123.456e789", while the following are not
+ * valid numbers: "abc", "1a", "1e", "e3", "99e2.5", "--6", "-+3", "95a54e53".
+ *
+ * Formally, a valid number is defined using one of the following definitions:
+ * - An integer number followed by an optional exponent.
+ * - A decimal number followed by an optional exponent.
+ *
+ * An integer number is defined with an optional sign '-' or '+' followed by digits.
+ * A decimal number is defined with an optional sign '-' or '+' followed by one of the
+ * following definitions:
+ * - Digits followed by a dot '.'.
+ * - Digits followed by a dot '.' followed by digits.
+ * - A dot '.' followed by digits.
+ * - An exponent is defined with an exponent notation 'e' or 'E' followed by an integer number.
+ *
+ * The digits are defined as one or more digits.
+ */
+
+/**
+ * @param {string} s
+ * @return {boolean}
+ */
+var isNumber = function(s) {
+  return s.trim().length && !isNaN(s.trim()) && !s.includes('Infinity');
+};