You are given a graph with X and Y axes. Each axis represents positive integers.
We will plot a graph based on given X and Y points.
Starting from (0,0), X will increment by 1 on the X axis.
The Y axis will represent the following format:
- If X is 0, Y is 0.
(0,0) - If X is 1, Y is 1.
(1,1) - If X is 2 or more, the X-th Y is
(X-1-th Y + X-2-th Y)
For example, if X = 2, Y = (0 + 1) = 1.
Given a series of (X, Y) points, a line will be drawn.
See the example image for visualization.
Write a function that takes input value X, and calculate the area underneath the drawn lines.
This problem asks you to generate a sequence of points from a Fibonacci-like recurrence, connect them with straight line segments, and compute the total area under the resulting polyline. The key is to treat the graph as a sum of trapezoids between consecutive points, which makes the solution straightforward once the Y-values are built. A careful linear pass is usually enough, and the main challenge is translating the recurrence and the geometry into a clean formula.
