universe@2: package de.uapcore.sudoku;
universe@2: 
universe@2: /**
universe@2:  *
universe@2:  * @author mike
universe@2:  */
universe@2: public final class Solver {
universe@2:     
universe@2:     public Solver() {
universe@2:     }
universe@2:     
universe@2:     public boolean check(Field f) {
universe@2:         int line[];
universe@2:         for (int i = 0 ; i < 9 ; i++) {
universe@2:             line = getRow(f, i);
universe@2:             if (!valid(line)) {
universe@2:                 return false;
universe@2:             }
universe@2:             line = getColumn(f, i);
universe@2:             if (!valid(line)) {
universe@2:                 return false;
universe@2:             }
universe@2:         }
universe@2:         
universe@2:         int square[][];
universe@2:         for (int x = 0 ; x < 3 ; x++) {
universe@2:             for (int y = 0 ; y < 3 ; y++) {
universe@2:                 square = getSquare(f, x, y);
universe@2:                 if (!valid(square)) {
universe@2:                     return false;
universe@2:                 }
universe@2:             }
universe@2:         }
universe@2:         
universe@2:         return true;
universe@2:     }
universe@2:     
universe@2:     private boolean complete(int[][] square) {
universe@2:         for (int x = 0 ; x < 3 ; x++) {
universe@2:             for (int y = 0 ; y < 3 ; y++) {
universe@2:                 if (square[x][y] == 0) {
universe@2:                     return false;
universe@2:                 }
universe@2:             }    
universe@2:         }
universe@2:         return true;
universe@2:     }
universe@2:     
universe@2:     private boolean complete(int[] line) {
universe@2:         for (int i = 0 ; i < 9 ; i++) {
universe@2:             if (line[i] == 0) {
universe@2:                 return false;
universe@2:             }
universe@2:         }
universe@2:         return true;
universe@2:     }
universe@2:     
universe@2:     private boolean valid(int[] line) {
universe@2:         int numbers[] = new int[9];
universe@2:         for (int i = 0 ; i < 9 ; i++) {
universe@2:             int l = line[i]-1;
universe@2:             if (l >= 0) {
universe@2:                 if (++numbers[l] > 1) {
universe@2:                     return false;
universe@2:                 }
universe@2:             }
universe@2:         }
universe@2:         
universe@2:         return true;
universe@2:     }
universe@2:     
universe@2:     private boolean valid(int[][] square) {
universe@2:         int[] line = new int[9];
universe@2:         for (int x = 0 ; x < 3 ; x++) {
universe@2:             for (int y = 0 ; y < 3 ; y++) {
universe@2:                 line[3*x+y] = square[x][y];
universe@2:             }    
universe@2:         }
universe@2:         return valid(line);
universe@2:     }
universe@2:     
universe@2:     private int[][] getSquare(Field f, int x, int y) {
universe@2:         if (x < 0 || x > 2 || y < 0 || y > 2) {
universe@2:             throw new IllegalArgumentException("Invalid square coordinates");
universe@2:         }
universe@2:         int[][] square = new int[3][3];
universe@2:         
universe@2:         for (int u = 0 ; u < 3 ; u++) {
universe@2:             for (int v = 0 ; v < 3 ; v++) {
universe@2:                 square[u][v] = f.getCellValue(3*x+u, 3*y+v);
universe@2:             }
universe@2:         }
universe@2:         
universe@2:         return square;
universe@2:     }
universe@2:     
universe@2:     private int[] getRow(Field f, int y) {
universe@2:         if (y < 0 || y > 8) {
universe@2:             throw new IllegalArgumentException("Invalid row number");
universe@2:         }
universe@2:         int row[] = new int[9];
universe@2:         
universe@2:         for (int x = 0 ; x < 9 ; x++) {
universe@2:             row[x] = f.getCellValue(x, y);
universe@2:         }
universe@2:         
universe@2:         return row;
universe@2:     }
universe@2:     
universe@2:     private int[] getColumn(Field f, int x) {
universe@2:         if (x < 0 || x > 8) {
universe@2:             throw new IllegalArgumentException("Invalid column number");
universe@2:         }
universe@2:         int column[] = new int[9];
universe@2:         
universe@2:         for (int y = 0 ; y < 9 ; y++) {
universe@2:             column[y] = f.getCellValue(x, y);
universe@2:         }
universe@2:         
universe@2:         return column;
universe@2:     }
universe@2: }