Add solution #816

Author: JoshCrozier

Diff for: README.md

@@ -624,6 +624,7 @@
 813|[Largest Sum of Averages](./0813-largest-sum-of-averages.js)|Medium|
 814|[Binary Tree Pruning](./0814-binary-tree-pruning.js)|Medium|
 815|[Bus Routes](./0815-bus-routes.js)|Hard|
+816|[Ambiguous Coordinates](./0816-ambiguous-coordinates.js)|Medium|
 819|[Most Common Word](./0819-most-common-word.js)|Easy|
 821|[Shortest Distance to a Character](./0821-shortest-distance-to-a-character.js)|Easy|
 824|[Goat Latin](./0824-goat-latin.js)|Easy|

Diff for: solutions/0816-ambiguous-coordinates.js

@@ -0,0 +1,72 @@
+/**
+ * 816. Ambiguous Coordinates
+ * https://leetcode.com/problems/ambiguous-coordinates/
+ * Difficulty: Medium
+ *
+ * We had some 2-dimensional coordinates, like "(1, 3)" or "(2, 0.5)". Then, we removed all commas,
+ * decimal points, and spaces and ended up with the string s.
+ * - For example, "(1, 3)" becomes s = "(13)" and "(2, 0.5)" becomes s = "(205)".
+ *
+ * Return a list of strings representing all possibilities for what our original coordinates could
+ * have been.
+ *
+ * Our original representation never had extraneous zeroes, so we never started with numbers like
+ * "00", "0.0", "0.00", "1.0", "001", "00.01", or any other number that can be represented with
+ * fewer digits. Also, a decimal point within a number never occurs without at least one digit
+ * occurring before it, so we never started with numbers like ".1".
+ *
+ * The final answer list can be returned in any order. All coordinates in the final answer have
+ * exactly one space between them (occurring after the comma.)
+ */
+
+/**
+ * @param {string} s
+ * @return {string[]}
+ */
+var ambiguousCoordinates = function(s) {
+  const digits = s.slice(1, s.length - 1);
+  const result = [];
+
+  for (let i = 1; i < digits.length; i++) {
+    const leftPart = digits.substring(0, i);
+    const rightPart = digits.substring(i);
+
+    const validLeftCoords = getValidCoordinates(leftPart);
+    const validRightCoords = getValidCoordinates(rightPart);
+
+    for (const left of validLeftCoords) {
+      for (const right of validRightCoords) {
+        result.push(`(${left}, ${right})`);
+      }
+    }
+  }
+
+  return result;
+};
+
+function getValidCoordinates(s) {
+  const coords = [];
+
+  if (isValidInteger(s)) {
+    coords.push(s);
+  }
+
+  for (let i = 1; i < s.length; i++) {
+    const integerPart = s.substring(0, i);
+    const decimalPart = s.substring(i);
+
+    if (isValidInteger(integerPart) && isValidDecimal(decimalPart)) {
+      coords.push(`${integerPart}.${decimalPart}`);
+    }
+  }
+
+  return coords;
+}
+
+function isValidInteger(s) {
+  return s === '0' || s[0] !== '0';
+}
+
+function isValidDecimal(s) {
+  return s[s.length - 1] !== '0';
+}