Add solution #3027

Author: JoshCrozier

README.md

@@ -2136,6 +2136,7 @@
 3021|[Alice and Bob Playing Flower Game](./solutions/3021-alice-and-bob-playing-flower-game.js)|Medium|
 3024|[Type of Triangle](./solutions/3024-type-of-triangle.js)|Easy|
 3025|[Find the Number of Ways to Place People I](./solutions/3025-find-the-number-of-ways-to-place-people-i.js)|Medium|
+3027|[Find the Number of Ways to Place People II](./solutions/3027-find-the-number-of-ways-to-place-people-ii.js)|Hard|
 3042|[Count Prefix and Suffix Pairs I](./solutions/3042-count-prefix-and-suffix-pairs-i.js)|Easy|
 3066|[Minimum Operations to Exceed Threshold Value II](./solutions/3066-minimum-operations-to-exceed-threshold-value-ii.js)|Medium|
 3068|[Find the Maximum Sum of Node Values](./solutions/3068-find-the-maximum-sum-of-node-values.js)|Hard|

solutions/3027-find-the-number-of-ways-to-place-people-ii.js

@@ -0,0 +1,68 @@
+/**
+ * 3027. Find the Number of Ways to Place People II
+ * https://leetcode.com/problems/find-the-number-of-ways-to-place-people-ii/
+ * Difficulty: Hard
+ *
+ * You are given a 2D array points of size n x 2 representing integer coordinates of some points
+ * on a 2D-plane, where points[i] = [xi, yi].
+ *
+ * We define the right direction as positive x-axis (increasing x-coordinate) and the left
+ * direction as negative x-axis (decreasing x-coordinate). Similarly, we define the up direction
+ * as positive y-axis (increasing y-coordinate) and the down direction as negative y-axis
+ * (decreasing y-coordinate)
+ *
+ * You have to place n people, including Alice and Bob, at these points such that there is exactly
+ * one person at every point. Alice wants to be alone with Bob, so Alice will build a rectangular
+ * fence with Alice's position as the upper left corner and Bob's position as the lower right
+ * corner of the fence (Note that the fence might not enclose any area, i.e. it can be a line).
+ * If any person other than Alice and Bob is either inside the fence or on the fence, Alice will
+ * be sad.
+ *
+ * Return the number of pairs of points where you can place Alice and Bob, such that Alice does not
+ * become sad on building the fence.
+ *
+ * Note that Alice can only build a fence with Alice's position as the upper left corner, and Bob's
+ * position as the lower right corner. For example, Alice cannot build either of the fences in the
+ * picture below with four corners (1, 1), (1, 3), (3, 1), and (3, 3), because:
+ * - With Alice at (3, 3) and Bob at (1, 1), Alice's position is not the upper left corner and Bob's
+ *   position is not the lower right corner of the fence.
+ * - With Alice at (1, 3) and Bob at (1, 1), Bob's position is not the lower right corner of the
+ *   fence.
+ */
+
+/**
+ * @param {number[][]} points
+ * @return {number}
+ */
+var numberOfPairs = function(points) {
+  points.sort((a, b) => a[0] === b[0] ? b[1] - a[1] : a[0] - b[0]);
+  let result = 0;
+
+  for (let i = 0; i < points.length; i++) {
+    const [, maxY] = points[i];
+    let minY = -Infinity;
+
+    for (let j = i + 1; j < points.length; j++) {
+      const [, y] = points[j];
+      if (y <= maxY && y > minY) {
+        let isValid = true;
+        for (let k = 0; k < points.length; k++) {
+          if (k !== i && k !== j) {
+            const [x, ky] = points[k];
+            if (x >= points[i][0] && x <= points[j][0]
+                && ky <= points[i][1] && ky >= points[j][1]) {
+              isValid = false;
+              break;
+            }
+          }
+        }
+        if (isValid) {
+          result++;
+          minY = y;
+        }
+      }
+    }
+  }
+
+  return result;
+};