Android Open Source - sudoku Sudoku Algorithm

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From Project

Back to project page sudoku.

License

The source code is released under:

GNU Lesser General Public License

Java Source Code

package com.hao.apps.sudoku.algorithm;
//from  w w  w .j av a  2s  .  com
import java.util.LinkedList;
import java.util.List;
import java.util.Random;


public class SudokuAlgorithm {

  public SudokuAlgorithm() {
    init(9);
  }

  public SudokuAlgorithm(int num) {
    init(num);
  }

  
  private int fieldNum;
  private byte[] layout = null;
  private byte[] outbytes = null;
  private int curPos;
  private Random random = new Random();
  
  private byte[] ansPosArr = null;
  private byte[][] ansArr = null;
  private boolean randomLayout = false;
  
  private String finalSodukuString = null;

  public void setRandomLayout(boolean r) {
    randomLayout = r;
  }
  
  
  public String returnSudokuPuzzleString(){
    return finalSodukuString;
  }

  private void init(int num) {
    
    curPos = 0;
    fieldNum = num;
    if (layout == null)
      layout = new byte[num * num];
    if (outbytes == null)
      outbytes = new byte[(num * num + 1) / 2];
    if (ansPosArr == null)
      ansPosArr = new byte[num * num];
    if (ansArr == null)
      ansArr = new byte[num * num][num];
    for (int i = 0; i < num * num; i++) {
      layout[i] = -1;
      ansPosArr[i] = 0;
      for (int j = 0; j < num; j++)
        ansArr[i][j] = -1;
    }
  }

  private void getAnswer(int pos) {
    for (byte i = 0; i < fieldNum; i++)
      ansArr[pos][i] = i;
    int x = pos / fieldNum, y = pos % fieldNum;
    for (int i = 0; i < fieldNum; i++) {
      if (layout[i * fieldNum + y] != -1)
        ansArr[pos][layout[i * fieldNum + y]] = -1;
      if (layout[x * fieldNum + i] != -1)
        ansArr[pos][layout[x * fieldNum + i]] = -1;
    }
    int subnum = (int) Math.sqrt(fieldNum);
    int x2 = x / subnum, y2 = y / subnum;
    for (int i = x2 * subnum; i < subnum + x2 * subnum; i++) {
      for (int j = y2 * subnum; j < subnum + y2 * subnum; j++) {
        if (layout[i * fieldNum + j] != -1)
          ansArr[pos][layout[i * fieldNum + j]] = -1;
      }
    }
    if (randomLayout == true)
      dealAnswer(pos);
  }

  
  private void dealAnswer(int pos) {
    List<Byte> list = new LinkedList<Byte>();
    for (int i = 0; i < fieldNum; i++)
      list.add(ansArr[pos][i]);
    int rdm = 0, idx = 0;
    while (list.size() != 0) {
      rdm = Math.abs(random.nextInt()) % list.size();
      ansArr[pos][idx] = list.get(rdm);
      list.remove(rdm);
      idx++;
    }
    list = null;
  }

  
  private int getAnswerCount(int pos) {
    int count = 0;
    for (int i = 0; i < fieldNum; i++)
      if (ansArr[pos][i] != -1)
        count++;
    return count;
  }

  private byte getAnswerNum(int fieldPos, int ansPos) {
    int cnt = 0;
    for (int i = 0; i < fieldNum; i++) {
      if (cnt == ansPos && ansArr[fieldPos][i] != -1)
        return ansArr[fieldPos][i];
      if (ansArr[fieldPos][i] != -1)
        cnt++;
    }
    return -1;
  }

  public long generate(long layoutCount) {
    curPos = 0;
    long count = 0;
    while (count < layoutCount || layoutCount == -1) {
      if (ansPosArr[curPos] == 0)
        getAnswer(curPos);
      int ansCount = getAnswerCount(curPos);
      if (ansCount == ansPosArr[curPos] && curPos == 0)
        break;
      if (ansCount == 0) {
        ansPosArr[curPos] = 0;
        curPos--;
        layout[curPos] = -1;
        continue;
      }
      else if (ansPosArr[curPos] == ansCount) {
        ansPosArr[curPos] = 0;
        curPos--;
        layout[curPos] = -1;
        continue;
      } else {
        layout[curPos] = getAnswerNum(curPos, ansPosArr[curPos]);
        ansPosArr[curPos]++;
        curPos++;
      }
      if (fieldNum * fieldNum == curPos) {
        outData();
        System.out.println();
        count++;
        curPos--;
        layout[curPos] = -1;
        ansPosArr[curPos] = 1;
      }
    }
    return count;
  }

  public void generateRandom(int count) {
    setRandomLayout(true);
    for (int i = 0; i < count; i++) {
      init(9);
      generate(1);
    }
  }
  
  public void outData() {
    String temp = "";
    for (int i = 0; i < fieldNum * fieldNum; i++) {
      if (layout[i] != -1){
        temp = temp + (layout[i] + 1);
      }  
    }
    finalSodukuString = temp;
  }

}

Java Source Code List

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