Add solution #972

Author: JoshCrozier

README.md

@@ -1,4 +1,4 @@
-# 1,055 LeetCode solutions in JavaScript
+# 1,056 LeetCode solutions in JavaScript
 
 [https://leetcode.com/](https://leetcode.com/)
 
@@ -780,6 +780,7 @@
 969|[Pancake Sorting](./solutions/0969-pancake-sorting.js)|Medium|
 970|[Powerful Integers](./solutions/0970-powerful-integers.js)|Easy|
 971|[Flip Binary Tree To Match Preorder Traversal](./solutions/0971-flip-binary-tree-to-match-preorder-traversal.js)|Medium|
+972|[Equal Rational Numbers](./solutions/0972-equal-rational-numbers.js)|Hard|
 976|[Largest Perimeter Triangle](./solutions/0976-largest-perimeter-triangle.js)|Easy|
 977|[Squares of a Sorted Array](./solutions/0977-squares-of-a-sorted-array.js)|Easy|
 985|[Sum of Even Numbers After Queries](./solutions/0985-sum-of-even-numbers-after-queries.js)|Easy|

solutions/0972-equal-rational-numbers.js

@@ -0,0 +1,49 @@
+/**
+ * 972. Equal Rational Numbers
+ * https://leetcode.com/problems/equal-rational-numbers/
+ * Difficulty: Hard
+ *
+ * Given two strings s and t, each of which represents a non-negative rational number, return true
+ * if and only if they represent the same number. The strings may use parentheses to denote the
+ * repeating part of the rational number.
+ *
+ * A rational number can be represented using up to three parts: <IntegerPart>, <NonRepeatingPart>,
+ * and a <RepeatingPart>. The number will be represented in one of the following three ways:
+ * - <IntegerPart>
+ *   - For example, 12, 0, and 123.
+ * - <IntegerPart><.><NonRepeatingPart>
+ *   - For example, 0.5, 1., 2.12, and 123.0001.
+ * - <IntegerPart><.><NonRepeatingPart><(><RepeatingPart><)>
+ *   - For example, 0.1(6), 1.(9), 123.00(1212).
+ *
+ * The repeating portion of a decimal expansion is conventionally denoted within a pair of round
+ * brackets. For example:
+ * - 1/6 = 0.16666666... = 0.1(6) = 0.1666(6) = 0.166(66).
+ */
+
+/**
+ * @param {string} s
+ * @param {string} t
+ * @return {boolean}
+ */
+var isRationalEqual = function(s, t) {
+  const valueS = parseRational(s);
+  const valueT = parseRational(t);
+  return Math.abs(valueS - valueT) < 1e-10;
+
+  function parseRational(str) {
+    const [integer, decimal] = str.split('.');
+    if (!decimal) return parseInt(integer, 10);
+
+    const openParen = decimal.indexOf('(');
+    if (openParen === -1) return parseInt(integer, 10) + parseFloat(`0.${decimal}`);
+
+    const nonRepeating = decimal.slice(0, openParen);
+    const repeating = decimal.slice(openParen + 1, -1);
+    const nonRepeatValue = nonRepeating ? parseFloat(`0.${nonRepeating}`) : 0;
+    const repeatValue = parseInt(repeating, 10) / (10 ** repeating.length - 1)
+      / (10 ** nonRepeating.length);
+
+    return parseInt(integer, 10) + nonRepeatValue + repeatValue;
+  }
+};