prev and curr, to represent the number of ways to place houses on one side of the street for the previous and current positions, respectively.prev to 1 and curr to 2, which corresponds to the base cases of the Fibonacci sequence.n, updating prev and curr at each step to reflect the Fibonacci sequence.curr as the sum of prev and the old curr, then update prev to the old curr.curr represents the number of ways to place houses on one side of the street for n plots.curr modulo 10^9 + 7 to get the total number of ways for both sides of the street.