/* package whatever; // don't place package name! */
 
import java.util.*;
import java.lang.*;
import java.io.*;
 
/* Name of the class has to be "Main" only if the class is public. */
class Ideone
{
	public static void main (String[] args) throws java.lang.Exception
	{
		// your code goes here
		int N = 5;
		int[] A = {0, 3, 5, 2, 1, 9};
		int[] B = {0, 1, 1, 10, 5, 3};
 
		int[][] dp = new int[N + 1][3];
 
		dp[1][0] = A[1];   //for a
		dp[1][2] = Integer.MAX_VALUE; //for b2
		dp[1][1] = B[1]; //for b1
 
		for(int i = 2; i <= N; i++){
			 int v1 = A[i] + Math.min(dp[i-1][2], dp[i-1][0]);
			 int v2 = B[i] + B[i-1] + Math.min(dp[i - 2][1], dp[i-2][0]);
			 int v3 = B[i] + Math.min(dp[i-1][1], dp[i-1][0]);
 
			 dp[i][0] = v1;
			 dp[i][2] = v2;
			 dp[i][1] = v3;
 
		}
 
		System.out.println(Math.min(dp[N][0], dp[N][2]));
	}
}

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