HW6.22

  1 import java.util.Arrays;
  2
  3 public class Solution
  4 {
  5     public static void main(String[] args)
  6     {
  7         int[][] chessboard = new int[8][8];
  8         int[][] answerSave = new int[92][8];
  9         int[] oneAnswer = new int[8];
 10
 11         while(true)
 12         {
 13             putQueens(chessboard);
 14
 15             if(judgeCorrect(chessboard) == true)
 16             {
 17                 oneAnswer = convert(chessboard);
 18                 if(!contain(answerSave, oneAnswer))
 19                 {
 20                     drawChessboard(chessboard);
 21                     putIn(answerSave, oneAnswer);
 22                     if(isFull(answerSave))
 23                         break;
 24                 }
 25                 else
 26                     clearChessboard(chessboard);
 27             }
 28             else
 29                 clearChessboard(chessboard);
 30         }
 31     }
 32
 33
 34     //put 8 queens on the chessboard randomly
 35     public static void putQueens(int[][] array)
 36     {
 37         int position;
 38
 39         for(int i = 0; i < 8; i++)
 40         {
 41             position = (int)(Math.random() * 8);
 42             array[i][position] = 1;
 43         }
 44     }
 45
 46     //clear the chessboard
 47     public static void clearChessboard(int[][] array)
 48     {
 49         for(int i = 0; i < 8; i++)
 50             for(int j = 0; j < 8; j++)
 51                 array[i][j] = 0;
 52     }
 53
 54     //judge if there is only one chess in a row
 55     public static boolean judgeRow(int[][] array, int x, int y)
 56     {
 57         for(int i = y - 1; i >= 0; i--)
 58             if(array[x][i] == 1)
 59                 return false;
 60         for(int i = y + 1; i < 8; i++)
 61             if(array[x][i] == 1)
 62                 return false;
 63         return true;
 64     }
 65
 66     //judge if there is only one chess in a column
 67     public static boolean judgeColumn(int[][] array, int x, int y)
 68     {
 69         for(int i = x - 1; i >= 0; i--)
 70             if(array[i][y] == 1)
 71                 return false;
 72         for(int i = x + 1; i < 8; i++)
 73             if(array[i][y] == 1)
 74                 return false;
 75         return true;
 76     }
 77
 78     //judge if there is only one chess in the lean from left-top to right-bottom
 79     public static boolean judgeLeanTopToBottom(int[][] array, int x, int y)
 80     {
 81         for(int i = x - 1, j = y - 1; i >= 0 && j >= 0; i--, j--)
 82             if(array[i][j] == 1)
 83                 return false;
 84         for(int i = x + 1, j = y + 1; i < 8 && j < 8; i++, j++)
 85             if(array[i][j] == 1)
 86                 return false;
 87         return true;
 88     }
 89
 90     //judge if there is only one chess in the lean from left-bottom to right-top
 91     public static boolean judgeLeanBottomToTop(int[][] array, int x, int y)
 92     {
 93         for(int i = x + 1, j = y - 1; i < 8 && j >= 0; i++, j--)
 94             if(array[i][j] == 1)
 95                 return false;
 96         for(int i = x - 1, j = y + 1; i >= 0 && j < 8; i--, j++)
 97             if(array[i][j] == 1)
 98                 return false;
 99         return true;
100     }
101
102     //judge if all the queens are put correctly
103     public static boolean judgeCorrect(int[][] array)
104     {
105         int[] putX = new int[8];
106         int[] putY = new int[8];
107
108         for(int i = 0; i < 8; i++)
109             for(int j = 0; j < 8; j++)
110                 if(array[i][j] == 1)
111                 {
112                     putX[i] = i;
113                     putY[i] = j;
114                     break;
115                 }
116
117         for(int i = 0; i < 8; i++)
118         {
119             if(!(judgeRow(array, putX[i], putY[i]) && judgeColumn(array, putX[i], putY[i])
120                 && judgeLeanTopToBottom(array, putX[i], putY[i]) && judgeLeanBottomToTop(array, putX[i], putY[i])))
121                 return false;
122         }
123         return true;
124     }
125
126     //convert the 2D chessboard in a 1D array
127     public static int[] convert(int[][] array)
128     {
129         int[] oneDQueen = new int[8];
130         for(int i = 0; i < 8; i++)
131             for(int j = 0; j < 8; j++)
132             {
133                 if(array[i][j] == 1)
134                     oneDQueen[i] = j;
135             }
136         return oneDQueen;
137     }
138
139     //judge if the answer has been found
140     public static boolean contain(int[][] largeArray, int[] littleArray)
141     {
142         for(int[] array: largeArray)
143             if(Arrays.equals(array, littleArray))
144                 return true;
145         return false;
146     }
147
148     //put the answer in the answer-save array
149     public static void putIn(int[][] largeArray, int[] littleArray)
150     {
151         int signI = 0;
152         for(int i = 0; i < 92; i++)
153             for(int j = 0; j < 7; j++)
154                 if(largeArray[i][j] == 0 && largeArray[i][j + 1] == 0)
155                 {
156                     signI = i;
157                     putIn(largeArray, littleArray, signI);
158                     return;
159                 }
160     }
161
162     public static void putIn(int[][] largeArray, int[] littleArray, int sign)
163     {
164         for(int i = 0; i < 8; i++)
165             largeArray[sign][i] = littleArray[i];
166     }
167
168     //judge if the array is full
169     public static boolean isFull(int[][] largeArray)
170     {
171         for(int j = 0; j < 8; j++)
172             if(largeArray[91][j] != 0)
173                 return true;
174         return false;
175     }
176
177     public static void drawChessboard(int[][] array)
178     {
179         for(int i = 0; i < 8; i++)
180         {
181             for(int j = 0; j < 8; j++)
182             {
183                 if(array[i][j] == 1)
184                     System.out.print("Q");
185                 else
186                     System.out.print("-");
187             }
188             System.out.println();
189         }
190     }
191 }