最小旅行线路-动规

Sample Input
3
1 1 2 2 3 3
Sample Output
9

import java.util.ArrayList;
import java.util.Scanner;


public class Main{
    static int dp[][]=new int[200005][2];
    static int map1[][]=new int[200005][2];

    public static void main(String[] args) {
        Scanner scanner=new Scanner(System.in);
        int n=scanner.nextInt();
        for (int i = 1; i <=2*n ; i++) {
            int x=scanner.nextInt();
            if (map1[x][0]==0)map1[x][0]=i;
            else map1[x][1]=i;
        }
        dp[1][1]=map1[1][1]-1;
        dp[1][0]=map1[1][0]-1;
        for (int i = 2; i <=n ; i++) {
            if (dp[i-1][1]+Math.abs(map1[i][0]-map1[i-1][1])+dp[i-1][0]+
                    Math.abs(map1[i][1]- map1[i-1][0])<dp[i-1][1]+
                    Math.abs(map1[i][1]-map1[i-1][1])+dp[i-1][0]+Math.abs(map1[i][0]- map1[i-1][0])){
                dp[i][0]=dp[i-1][1]+Math.abs(map1[i][0]-map1[i-1][1]);
                dp[i][1]=dp[i-1][0]+Math.abs(map1[i][1]-map1[i-1][0]);
            }else {
                dp[i][1]=dp[i-1][1]+Math.abs(map1[i][1]-map1[i-1][1]);
                dp[i][0]=dp[i-1][0]+Math.abs(map1[i][0]-map1[i-1][0]);
            }
        }
        System.out.println(dp[n][1]+dp[n][0]);

    }
}