42. Trapping Rain Water

Two Pointers — O(n) time, O(1) space

Example 1
Example 2
V-Shape
Complex
Staircase
W-Shape
5x
Bar
Water
Left Pointer
Right Pointer
leftMax
rightMax
Water: 0
Left: 0
Right: -
leftMax: 0
rightMax: 0
Total Water Trapped: 0 units
Ready. Press Step or Play to begin.