feat: monday

pkg/trapping_rain_water/main.go

@@ -0,0 +1,31 @@
+package trapping_rain_water
+
+func Trap(heights []int) int {
+	// Calculate area taken up by the boundary.
+	boundary_area := 0
+	for _, height := range heights {
+		boundary_area += height
+	}
+
+	// Calculate the total area taken up by the boundary and the water.
+	total_area := 0
+	left := 0
+	left_height := 0
+	right := len(heights) - 1
+	right_height := 0
+
+	for left <= right {
+		left_height = max(left_height, heights[left])
+		right_height = max(right_height, heights[right])
+
+		if left_height < right_height {
+			total_area += left_height
+			left++
+		} else {
+			total_area += right_height
+			right--
+		}
+	}
+
+	return total_area - boundary_area
+}