Best Time to Buy and Sell Stock with Cooldown

class Solution {
    public int maxProfit(int[] prices) {
       // return solve(prices,0,false);
        return dp(prices);
    }
    public int solve(int [] prices,int idx,boolean is){
        if(idx>=prices.length)
            return 0;
        if(is){
            // stock sell
            int a=solve(prices,idx+2,false)+prices[idx];
            //stock retain
            int b=solve(prices,idx+1,true);
            return Math.max(a,b);
        }
        //stock buy 
        int a=solve(prices,idx+1,true)-prices[idx];
        //stock dont buy
        int b=solve(prices,idx+1,false);
         return Math.max(a,b);
    }
    public int dp(int [] prices){
        int [][] arr=new int[2][prices.length+2];
        for(int col=prices.length-1;col>=0;col--){
            //row==0
            arr[0][col]=Math.max(arr[1][col+1]-prices[col],arr[0][col+1]);
            //row==1
            arr[1][col]=Math.max(arr[0][col+2]+prices[col],arr[1][col+1]);
        }
        return arr[0][0];
    }
}