记忆功能背包

Question

好的，我遇到了背包问题的Memory Function实现问题。我的实现如果在Java中给我错误的答案但在C ++中相同的实现给了我正确的答案。

import java.io.*;
import java.util.*;

public class KnapsackMF {

    public static void main(String args[]){
        int wt;
        int vl;
        long start, end, runTime;
        Scanner input = new Scanner(System.in);
        int n, W;

        System.out.println("Please enter the number of items: ");
        n = input.nextInt();

        System.out.println("Please enter the capacity of the knapsack: ");
        W = input.nextInt();

        int[][] V = new int[n+1][W+1];
        int[] Wt = new int[n];
        int[] Vl = new int[n];

        for(int i = 0; i < n; i++){
            System.out.println("Enter the weight and the value of item " + i + ": ");
            wt = input.nextInt();
            vl = input.nextInt();

            Wt[i] = wt;
            Vl[i] = vl;
        }

        for(int i = 0; i <= n; i++ ){
            for(int j = 0; j <= W; j++){
                if(j == 0 || i == 0){
                    V[i][j] = 0;
                }
                else{
                    V[i][j] = -1;
                }
            }
        }
        /*
        for(int i= 0; i <= n; i++){
                for(int j = 0; j <= W; j++){
                    System.out.print(V[i][j] + " ");
                }
            System.out.println();
        }
        */

        start = System.nanoTime();

        System.out.println("The highest value is: " + MFKnapsack(n, W, V, Vl, Wt));

        end = System.nanoTime();
        runTime = (end - start);

        System.out.println("Nanoseconds: " + runTime);


        for(int i= 0; i <= n; i++){
                for(int j = 0; j <= W; j++){
                      System.out.print(V[i][j] + " ");
                }
                System.out.println();
        }

        //system("PAUSE");
    }

    public static int MFKnapsack(int i, int j, int[][] V, int[] Vl, int[] Wt){
        int value = 0;

        if(V[i][j] < 0){
             if(j < Wt[i-1]){
                  value = MFKnapsack(i-1, j, V, Vl, Wt);
             }
             else{
                  value = Math.max(MFKnapsack(i-1, j, V, Vl, Wt), Vl[i-1] + MFKnapsack(i-1, j-Wt[i-1], V, Vl, Wt));
             }
        }
        V[i][j] = value;
        return V[i][j];

    }

}

我使用的例子不在我的书中，输入应该是：

4

5

2 12

1 10

3 20

2 15

对此的答案应该是37，但是有些情况正在发生，我没有看到，它给了我35个。