Question

我有这个用于回溯的psudocode来找到从单元格向后的路径（6,6）。

如果F [i - 1，j]> F [i，j - 1]然后到（i，j）的路径来自上面。如果F [i - 1，j]＆lt; F [i，j - 1]然后到（i，j）的路径来自剩下。如果F [i - 1，j] = F [i，j - 1]那么任何一个方向都可以工作＆＃34;

我不知道如何修改我的代码来执行此操作，但我确定它介于**代码之间，我希望它打印出代码遍历的路径的索引，例如因为它应该打印类似于（6,6）（5,6）（4,6）（4,5）（4,4）（3,4）（3,3）（2,3）（1,3）（1,2）（1,1）

import java.util.Random;
public class project {
private static int max(int i, int j) {
    return i > j ? i : j;
}
public static int collect(int[][] board) {

    int rowLen = board.length;
    int columnLen = board[0].length;
    int[][] F = new int[rowLen][columnLen];
    F[0][0] = (int) board[0][0];


    for (int column = 1; column < columnLen; column++) {
        F[0][column] = (int)(F[0][column - 1] + board[0][column]);
    }

    **for (int row = 1; row < rowLen; row++) {
        F[row][0] = (int)(F[row - 1][0] + board[row][0]);
        for (int column = 1; column < columnLen; column++) {
            F[row][column] = (int)(max(F[row - 1][column],
                F[row][column - 1]) + board[row][column]);**
        }  
    }   

    System.out.println("-------------------------------------------");
    System.out.println("maxpath board");
    for (int row = 0; row < 6; row++) {
        for (int column = 0; column < 6; column++) {
            System.out.print(F[row][column] + "  ");
        }
        System.out.println();

    }

    return F[rowLen - 1][columnLen - 1];
}
public static void main(String[] args) {
    //create the grid
    final int rowWidth = 6;
    final int colHeight = 6;
    final int[] coinvalues = {
        0,
        1
    };
    Random rand = new Random();
    int[][] board = new int[rowWidth][colHeight];
    for (int[] board1: board) {
        for (int col = 0; col < board1.length; col++) {
            board1[col] = coinvalues[rand.nextInt(coinvalues.length)];
        }
    }System.out.println("coinboard");
    //display output
    for (int[] board1: board) {
        for (int j = 0; j < board1.length; j++) {
            System.out.print(board1[j] + " ");
            //System.out.println();
        }
        System.out.println();
    }
    System.out.println("Maximum Coins : " + collect(board));

}
}
sample output- coinboard
1 0 1 1 1 0 
0 0 1 0 0 0 
0 0 1 0 1 0 
1 0 1 0 1 1 
0 1 0 1 0 1 
1 1 1 1 0 1 
-------------------------------------------
maxpath board
1  1  2  3  4  4  
1  1  3  3  4  4  
1  1  4  4  5  5  
2  2  5  5  6  7  
2  3  5  6  6  8  
3  4  6  7  7  9


Maximum Coins : 9

Answer 1

这是我对你的问题进行编辑以完成任务（顺便说一句，我的代码总是优先考虑向上移动而不是在回溯时左移同时获得相同的利润） -

/* package whatever; // don't place package name! */

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

import java.util.Random;
class project {
private static int max(int i, int j) {
    return i > j ? i : j;
}
public static void paste(int i,int j){
    System.out.println("("+i+","+j+")");
}
public static int collect(int[][] board) {

    int rowLen = board.length;
    int columnLen = board[0].length;
    int[][] F = new int[rowLen][columnLen];
    F[0][0] = (int) board[0][0];


    for (int column = 1; column < columnLen; column++) {
        F[0][column] = (int)(F[0][column - 1] + board[0][column]);
    }

    for (int row = 1; row < rowLen; row++) {
        F[row][0] = (int)(F[row - 1][0] + board[row][0]);
        for (int column = 1; column < columnLen; column++) {
            F[row][column] = (int)(max(F[row - 1][column],
                F[row][column - 1]) + board[row][column]);
        }  
    }   

    System.out.println("-------------------------------------------");
    System.out.println("maxpath board");
    for (int row = 0; row < 6; row++) {
        for (int column = 0; column < 6; column++) {
            System.out.print(F[row][column] + "  ");
        }
        System.out.println();

}
int curr=F[rowLen - 1][columnLen - 1];
int i=rowLen-1;
int j=columnLen-1;
paste(i+1,j+1);
while(i>0&&j>0){

    if(i>0&&F[i-1][j]==curr){
        i=i-1;
    }
    else if(j>0&&F[i][j-1]==curr){
        j=j-1;
    }
    else if(i>0&&F[i-1][j]==curr-1){    
        i=i-1;
        curr--;
        paste(i+1,j+1);
    }
    else if(j>0&&F[i][j-1]==curr-1){    
        j=j-1;
        curr--;
        paste(i+1,j+1);
    }

}
    return F[rowLen - 1][columnLen - 1];
}
public static void main(String[] args) {
    //create the grid
    final int rowWidth = 6;
    final int colHeight = 6;
    final int[] coinvalues = {
        0,
        1
    };
    Random rand = new Random();
    int[][] board = new int[rowWidth][colHeight];
    for (int[] board1: board) {
        for (int col = 0; col < board1.length; col++) {
            board1[col] = coinvalues[rand.nextInt(coinvalues.length)];
        }
    }System.out.println("coinboard");
    //display output
    for (int[] board1: board) {
        for (int j = 0; j < board1.length; j++) {
            System.out.print(board1[j] + " ");
            //System.out.println();
        }
        System.out.println();
    }
    System.out.println("Maximum Coins : " + collect(board));

}
}

为最大硬币收集添加回溯算法？

1 个答案: