Create Trappingrainwater.py

C++/Trappingrainwater.py

@@ -0,0 +1,42 @@
+# Python program to find maximum amount of water that can
+# be trapped within given set of bars.
+
+def findWater(arr, n):
+
+	# left[i] contains height of tallest bar to the
+	# left of i'th bar including itself
+	left = [0]*n
+
+	# Right [i] contains height of tallest bar to
+	# the right of ith bar including itself
+	right = [0]*n
+
+	# Initialize result
+	water = 0
+
+	# Fill left array
+	left[0] = arr[0]
+	for i in range( 1, n):
+		left[i] = max(left[i-1], arr[i])
+
+	# Fill right array
+	right[n-1] = arr[n-1]
+	for i in range(n-2, -1, -1):
+		right[i] = max(right[i + 1], arr[i]);
+
+	# Calculate the accumulated water element by element
+	# consider the amount of water on i'th bar, the
+	# amount of water accumulated on this particular
+	# bar will be equal to min(left[i], right[i]) - arr[i] .
+	for i in range(0, n):
+		water += min(left[i], right[i]) - arr[i]
+
+	return water
+
+
+# Driver program
+
+arr = [0, 1, 0, 2, 1, 0, 1, 3, 2, 1, 2, 1]
+n = len(arr)
+print("Maximum water that can be accumulated is", findWater(arr, n))
+