feat(array): add Trapping Rain Water solution

work/Hard/Array/42.trapping-rain-water.js

@@ -0,0 +1,44 @@
+/*
+ * 42. Trapping Rain Water
+ * Difficulty: Hard
+ * https://leetcode.com/problems/trapping-rain-water/
+ * 
+ * ──────────────────────────────────────────────────
+ * 
+ * Given n non-negative integers representing an elevation map where the
+ * width of each bar is 1, compute how much water it can trap after
+ * raining.
+ * 
+ *  
+ * 
+ * Example 1:
+ * 
+ * Input: height = [0,1,0,2,1,0,1,3,2,1,2,1]
+ * Output: 6
+ * Explanation: The above elevation map (black section) is represented
+ * by array [0,1,0,2,1,0,1,3,2,1,2,1]. In this case, 6 units of rain
+ * water (blue section) are being trapped.
+ * 
+ * Example 2:
+ * 
+ * Input: height = [4,2,0,3,2,5]
+ * Output: 9
+ * 
+ *  
+ * 
+ * Constraints:
+ * 
+ * 	• n == height.length
+ * 
+ * 	• 1 <= n <= 2 * 10^4
+ * 
+ * 	• 0 <= height[i] <= 10^5
+*/
+
+/**
+ * @param {number[]} height
+ * @return {number}
+ */
+var trap = function(height) {
+    
+};