使用递归的骑士之旅答案

【问题标题】：Knight's tour using recursion使用递归的骑士之旅
【发布时间】：2017-01-16 20:35:22
【问题描述】：

现在我正处于骑士之旅的关键时刻，我只希望骑士能够移动，直到他不能再移动，然后停止。该代码在大多数情况下都可以正常工作，但有时代码会打印出两个相同的数字。

来自我的移动功能的代码：

    board[0][0] = 1;

    if (row + 1 > -1 && row + 1 < 5 && col + 2 > -1 && col + 2 < 5 && board[row + 1][col + 2] == 0) {
        move++;
        row += 1;
        col += 2;
        board[row][col] = move;
        printBoard();
        system("pause");
        moveKnight(row, col, move);
    }

    else if (row + 1 > -1 && row + 1 < 5 && col - 2 > -1 && col - 2 < 5 && board[row + 1][col - 2] == 0) {
        move++;
        row += 1;
        col -= 2;
        board[row][col] = move;
        printBoard();
        system("pause");
        moveKnight(row, col, move);
    }

    else if (row - 1 > -1 && row - 1 < 5 && col + 2 > -1 && col + 2 < 5 && board[row - 1][col + 2] == 0) {
        move++;
        row -= 1;
        col += 2;
        board[row][col] = move;
        printBoard();
        system("pause");
        moveKnight(row, col, move);
    }

    else if (row - 1 > -1 && row - 1 < 5 && col - 2 > -1 && col - 2 < 5 && board[row - 1][col - 2] == 0) {
        move++;
        row -= 1;
        col -= 2;
        board[row][col] = move;
        printBoard();
        system("pause");
        moveKnight(row, col, move);
    }

    else if (row - 2 > -1 && row - 2 < 5 && col + 1 > -1 && col + 1 < 5 && board[row - 2][col + 1] == 0) {
        move++;
        row -= 2;
        col += 1;
        board[row][col] = move;
        printBoard();
        system("pause");
        moveKnight(row, col, move);
    }

    else if (row - 2 > -1 && row - 2 < 5 && col - 1 > -1 && col - 1 < 5 && board[row - 2][col - 1] == 0) {
        move++;
        row -= 2;
        col -= 1;
        board[row][col] = move;
        printBoard();
        system("pause");
        moveKnight(row, col, move);
    }

    else if (row + 2 > -1 && row + 2 < 5 && col + 1 > -1 && col + 1 < 5 && board[row + 2][col + 1] == 0) {
        move++;
        row += 2;
        col += 1;
        board[row][col] = move;
        printBoard();
        system("pause");
        moveKnight(row, col, move);
    }

    else if (row + 2 > -1 && row + 2 < 5 && col - 1 > -1 && col - 1 < 5 && board[row + 2][col - 1] == 0) {
        move++;
        row += 2;
        col -= 1;
        board[row][col] = move;
        printBoard();
        system("pause");
        moveKnight(row, col, move);
    }
}

输出：

  1  0  0  0  0
  0  0  2  0  0
  0  0  0  0  0
  0  0  0  0  0
  0  0  0  0  0
Press any key to continue . . .

  1  0  0  0  0
  0  0  2  0  0
  0  0  0  0  3
  3  0  0  0  0
  0  0  0  0  0
Press any key to continue . . .

  1  0  0  0  0
  0  0  2  0  0
  0  0  0  0  3
  3  0  4  0  0
  0  0  0  0  0
Press any key to continue . . .

  1  0  0  0  0
  0  0  2  0  0
  0  0  0  0  3
  3  0  4  0  0
  0  0  0  0  5
Press any key to continue . . .

  1  0  0  0  0
  0  0  2  0  0
  0  0  0  6  3
  3  0  4  0  0
  0  0  0  0  5
Press any key to continue . . .

  1  0  0  0  0
  0  0  2  0  0
  0  0  0  6  3
  3  7  4  0  0
  0  0  0  0  5
Press any key to continue . . .

  1  0  0  0  0
  0  0  2  0  0
  0  0  0  6  3
  3  7  4  0  0
  0  0  0  8  5
Press any key to continue . . .

  1  0  0  0  0
  0  0  2  0  0
  0  0  9  6  3
  3  7  4  0  0
  0  0  0  8  5
Press any key to continue . . .

  1  0  0  0  0
  0  0  2  0  0
  0  0  9  6  3
  3  7  4  0 10
 10  0  0  8  5
Press any key to continue . . .

  1  0  0  0  0
  0  0  2  0  0
  0  0  9  6  3
  3  7  4  0 10
 10  0 11  8  5
Press any key to continue . . .

  1  0  0  0  0
  0  0  2  0  0
  0 12  9  6  3
  3  7  4  0 10
 10  0 11  8  5
Press any key to continue . . .

  1  0  0  0  0
  0  0  2  0  0
  0 12  9  6  3
  3  7  4 13 10
 10  0 11  8  5
Press any key to continue . . .

  1  0  0  0  0
  0  0  2  0  0
  0 12  9  6  3
  3  7  4 13 10
 10 14 11  8  5
Press any key to continue . . .

  1  0  0  0  0
  0  0  2  0 15
 15 12  9  6  3
  3  7  4 13 10
 10 14 11  8  5
Press any key to continue . . .

  1 16  0  0  0
  0  0  2  0 15
 15 12  9  6  3
  3  7  4 13 10
 10 14 11  8  5
Press any key to continue . . .

  1 16  0  0  0
  0  0  2 17 15
 15 12  9  6  3
  3  7  4 13 10
 10 14 11  8  5
Press any key to continue . . .

打印板功能：

void printBoard() {
    cout << endl;
    for (int i = 0; i < 5; i++) {
        for (int j = 0; j < 5; j++) {
            cout << setw(3) << board[i][j];
        }
            cout << endl;
    }

}

整个程序：

// ConsoleApplication15.cpp : Defines the entry point for the console  application.


#include "stdafx.h"
#include <iostream>
#include <iomanip>

using namespace std;

void makeBoard();
void moveKnight(int row, int col, int move);
void printBoard();

int board[4][4];

int main()
{
    int row = 0;
int col = 0;
int move = 1;

makeBoard();
moveKnight(0, 0, 1);
printBoard();



system("pause");
return 0;
}

void makeBoard() {
for (int i = 0; i < 5; i++) {
    for (int j = 0; j < 5; j++) {
        board[i][j] = 0;

    }
}

}

void printBoard() {
cout << endl;
for (int i = 0; i < 5; i++) {
    for (int j = 0; j < 5; j++) {
        cout << setw(3) << board[i][j];
    }
    cout << endl;
}

}

void moveKnight(int row, int col, int move) {

board[0][0] = 1;

    if (row + 1 > -1 && row + 1 < 5 && col + 2 > -1 && col + 2 < 5 && board[row + 1][col + 2] == 0) {
        move++;
        row += 1;
        col += 2;
        board[row][col] = move;
        printBoard();
        system("pause");
        moveKnight(row, col, move);
    }

    else if (row + 1 > -1 && row + 1 < 5 && col - 2 > -1 && col - 2 < 5 && board[row + 1][col - 2] == 0) {
        move++;
        row += 1;
        col -= 2;
        board[row][col] = move;
        printBoard();
        system("pause");
        moveKnight(row, col, move);
    }

    else if (row - 1 > -1 && row - 1 < 5 && col + 2 > -1 && col + 2 < 5 && board[row - 1][col + 2] == 0) {
        move++;
        row -= 1;
        col += 2;
        board[row][col] = move;
        printBoard();
        system("pause");
        moveKnight(row, col, move);
    }

    else if (row - 1 > -1 && row - 1 < 5 && col - 2 > -1 && col - 2 < 5 && board[row - 1][col - 2] == 0) {
        move++;
        row -= 1;
        col -= 2;
        board[row][col] = move;
        printBoard();
        system("pause");
        moveKnight(row, col, move);
    }

    else if (row - 2 > -1 && row - 2 < 5 && col + 1 > -1 && col + 1 < 5 && board[row - 2][col + 1] == 0) {
        move++;
        row -= 2;
        col += 1;
        board[row][col] = move;
        printBoard();
        system("pause");
        moveKnight(row, col, move);
    }

    else if (row - 2 > -1 && row - 2 < 5 && col - 1 > -1 && col - 1 < 5 && board[row - 2][col - 1] == 0) {
        move++;
        row -= 2;
        col -= 1;
        board[row][col] = move;
        printBoard();
        system("pause");
        moveKnight(row, col, move);
    }

    else if (row + 2 > -1 && row + 2 < 5 && col + 1 > -1 && col + 1 < 5 && board[row + 2][col + 1] == 0) {
        move++;
        row += 2;
        col += 1;
        board[row][col] = move;
        printBoard();
        system("pause");
        moveKnight(row, col, move);
    }

    else if (row + 2 > -1 && row + 2 < 5 && col - 1 > -1 && col - 1 < 5 && board[row + 2][col - 1] == 0) {
        move++;
        row += 2;
        col -= 1;
        board[row][col] = move;
        printBoard();
        system("pause");
        moveKnight(row, col, move);
    }
}

【问题讨论】：

必须在 ifs 某处。请注意，第二步并不总是有效的（查看 3s 和 10s）。我建议重构你的代码，以便更容易理解发生了什么。
@code11 我怎样才能让它更容易理解？是的，问题出在第三步和第十步。我不知道为什么要打印两次
欢迎来到 Stack Overflow！听起来您可能需要学习如何使用调试器来逐步执行代码。使用好的调试器，您可以逐行执行您的程序，并查看它与您期望的偏差在哪里。如果您要进行任何编程，这是必不可少的工具。延伸阅读：How to debug small programs
@NathanOliver 我试过使用调试器。我还是找不到问题
你能告诉我们你的 printBoard() 函数吗？似乎总是在将重复值写入一行的最后一列时打印重复值（然后下一行的第一列重复该值），对吗？所以这可能只是一个打印问题......

标签： c++ recursion knights-tour

【解决方案1】：

尝试将int board[4][4]; 替换为int board[5][5]; :-)

【讨论】：

感谢您的帮助。我不敢相信它一直这么简单:)