Add solution #812

Author: JoshCrozier

README.md

@@ -620,6 +620,7 @@
 809|[Expressive Words](./0809-expressive-words.js)|Medium|
 810|[Chalkboard XOR Game](./0810-chalkboard-xor-game.js)|Hard|
 811|[Subdomain Visit Count](./0811-subdomain-visit-count.js)|Medium|
+812|[Largest Triangle Area](./0812-largest-triangle-area.js)|Easy|
 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|

solutions/0812-largest-triangle-area.js

@@ -0,0 +1,35 @@
+/**
+ * 812. Largest Triangle Area
+ * https://leetcode.com/problems/largest-triangle-area/
+ * Difficulty: Easy
+ *
+ * Given an array of points on the X-Y plane points where points[i] = [xi, yi], return the area of
+ * the largest triangle that can be formed by any three different points. Answers within 10-5 of
+ * the actual answer will be accepted.
+ */
+
+/**
+ * @param {number[][]} points
+ * @return {number}
+ */
+var largestTriangleArea = function(points) {
+  let maxArea = 0;
+
+  for (let i = 0; i < points.length; i++) {
+    for (let j = i + 1; j < points.length; j++) {
+      for (let k = j + 1; k < points.length; k++) {
+        const area = calculateTriangleArea(points[i], points[j], points[k]);
+        maxArea = Math.max(maxArea, area);
+      }
+    }
+  }
+
+  return maxArea;
+};
+
+function calculateTriangleArea(p1, p2, p3) {
+  const [[x1, y1], [x2, y2], [x3, y3]] = [p1, p2, p3];
+  return Math.abs(
+    (x1 * (y2 - y3) + x2 * (y3 - y1) + x3 * (y1 - y2)) / 2
+  );
+}