Name the right edge of a window
Updated
R is the rightmost index in the window. a[R] is the cell sitting there. Inclusive-inclusive: R is inside, R+1 is not.
What to focus on
Every index > R is outside. For a non-empty window 0 ≤ L ≤ R ≤ n-1.
Worked examples
right of a middle window
a = [4, 1, 9, 1], L=0 R=2- right edge is index 2
- a[2] = 9
- index 3 is outside
Result: R = 2
right of one cell
a = [7], L=0 R=0- n = 1
- the only legal right edge is 0
Result: R = 0
right of a string window
s = "abca", L=0 R=2- right edge is index 2
- s[2] = c
Result: R = 2
Try it
Write rightEdge(L, R). L is the left index. R is the right index. The window includes a[L] through a[R]. R is inclusive. Return R. On a=[4, 1, 9, 1] with (0, 2); a=[7] with (0, 0); s="abca" with (0, 2).
a (or s) is nonempty. 0 ≤ L ≤ R < n.