trapping rainwater problem in O(1) space

Code/trapping rainwater problem in O(1) space

@@ -0,0 +1,40 @@
+def findWater(arr,n): 
+
+    result = 0
+
+
+    left_max = 0
+    right_max = 0
+
+    lo = 0
+    hi = n-1
+
+    while(lo <= hi):  
+
+        if(arr[lo] < arr[hi]): 
+
+            if(arr[lo] > left_max): 
+
+                left_max = arr[lo] 
+            else: 
+
+                result += left_max - arr[lo] 
+            lo+=1
+
+        else: 
+
+            if(arr[hi] > right_max): 
+
+                right_max = arr[hi] 
+            else: 
+                result += right_max - arr[hi] 
+            hi-=1
+
+    return result 
+
+
+arr = [int(x) for x in input().split()] 
+n = len(arr) 
+
+print("Maximum water that can be accumulated is ", 
+        findWater(arr, n))