Add solution #593

Author: JoshCrozier

README.md

@@ -460,6 +460,7 @@
 590|[N-ary Tree Postorder Traversal](./0590-n-ary-tree-postorder-traversal.js)|Easy|
 591|[Tag Validator](./0591-tag-validator.js)|Hard|
 592|[Fraction Addition and Subtraction](./0592-fraction-addition-and-subtraction.js)|Medium|
+593|[Valid Square](./0593-valid-square.js)|Medium|
 594|[Longest Harmonious Subsequence](./0594-longest-harmonious-subsequence.js)|Easy|
 599|[Minimum Index Sum of Two Lists](./0599-minimum-index-sum-of-two-lists.js)|Easy|
 605|[Can Place Flowers](./0605-can-place-flowers.js)|Easy|

solutions/0593-valid-square.js

@@ -0,0 +1,38 @@
+/**
+ * 593. Valid Square
+ * https://leetcode.com/problems/valid-square/
+ * Difficulty: Medium
+ *
+ * Given the coordinates of four points in 2D space p1, p2, p3 and p4, return true if the
+ * four points construct a square.
+ *
+ * The coordinate of a point pi is represented as [xi, yi]. The input is not given in any order.
+ *
+ * A valid square has four equal sides with positive length and four equal angles (90-degree
+ * angles).
+ */
+
+/**
+ * @param {number[]} p1
+ * @param {number[]} p2
+ * @param {number[]} p3
+ * @param {number[]} p4
+ * @return {boolean}
+ */
+var validSquare = function(p1, p2, p3, p4) {
+  const helper = (a, b) => (a[0] - b[0]) ** 2 + (a[1] - b[1]) ** 2;
+  const points = [p1, p2, p3, p4];
+  const set = new Set();
+
+  for (let i = 0; i < 4; i++) {
+    for (let j = i + 1; j < 4; j++) {
+      const d = helper(points[i], points[j]);
+      if (!d) {
+        return false;
+      }
+      set.add(d);
+    }
+  }
+
+  return set.size === 2;
+};