Given an integer array A of non-negative integers representing an elevation map where the width of each bar is 1, compute how much water it is able to trap after raining.
1 <= |A| <= 100000
The only argument given is integer array A.
Return the total water it is able to trap after raining.
A = [0, 1, 0, 2, 1, 0, 1, 3, 2, 1, 2, 1]
A = [1, 2]
In this case, 6 units of rain water (blue section) are being trapped.
No water is trapped.
NOTE: You only need to implement the given function. Do not read input, instead use the arguments to the function. Do not print the output, instead return values as specified. Still have a question? Checkout Sample Codes for more details.