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Extracted 'constraints' methods and renamed coverBoard variable

This commit is contained in:
iaforek 2018-02-04 11:02:54 +00:00
parent 0f909270af
commit 66f5474f7f
1 changed files with 50 additions and 37 deletions
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87
algorithms/src/main/java/com/baeldung/algorithms/sudoku/DancingLinksAlgorithm.java
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@ -39,70 +39,83 @@ public class DancingLinksAlgorithm {
}
private boolean[][] createExactCoverBoard() {
boolean[][] R = new boolean[BOARD_SIZE * BOARD_SIZE * MAX_VALUE][BOARD_SIZE * BOARD_SIZE * CONSTRAINTS];
boolean[][] coverBoard = new boolean[BOARD_SIZE * BOARD_SIZE * MAX_VALUE][BOARD_SIZE * BOARD_SIZE * CONSTRAINTS];
int hBase = 0;
// Cell constraint.
for (int r = COVER_START_INDEX; r <= BOARD_SIZE; r++) {
for (int c = COVER_START_INDEX; c <= BOARD_SIZE; c++, hBase++) {
for (int n = COVER_START_INDEX; n <= BOARD_SIZE; n++) {
int index = getIndex(r, c, n);
R[index][hBase] = true;
}
}
}
// Row constrain.
for (int r = COVER_START_INDEX; r <= BOARD_SIZE; r++) {
for (int n = COVER_START_INDEX; n <= BOARD_SIZE; n++, hBase++) {
for (int c1 = COVER_START_INDEX; c1 <= BOARD_SIZE; c1++) {
int index = getIndex(r, c1, n);
R[index][hBase] = true;
}
}
}
// Column constraint.
for (int c = COVER_START_INDEX; c <= BOARD_SIZE; c++) {
for (int n = COVER_START_INDEX; n <= BOARD_SIZE; n++, hBase++) {
for (int r1 = COVER_START_INDEX; r1 <= BOARD_SIZE; r1++) {
int index = getIndex(r1, c, n);
R[index][hBase] = true;
}
}
}
hBase = checkCellConstraint(coverBoard, hBase);
hBase = checkRowConstraint(coverBoard, hBase);
hBase = checkColumnConstraint(coverBoard, hBase);
checkSubsectionConstraint(coverBoard, hBase);
// Subsection constraint
return coverBoard;
}
private int checkSubsectionConstraint(boolean[][] coverBoard, int hBase) {
for (int br = COVER_START_INDEX; br <= BOARD_SIZE; br += SUBSECTION_SIZE) {
for (int bc = COVER_START_INDEX; bc <= BOARD_SIZE; bc += SUBSECTION_SIZE) {
for (int n = COVER_START_INDEX; n <= BOARD_SIZE; n++, hBase++) {
for (int rDelta = 0; rDelta < SUBSECTION_SIZE; rDelta++) {
for (int cDelta = 0; cDelta < SUBSECTION_SIZE; cDelta++) {
int index = getIndex(br + rDelta, bc + cDelta, n);
R[index][hBase] = true;
coverBoard[index][hBase] = true;
}
}
}
}
}
return R;
return hBase;
}
private int checkColumnConstraint(boolean[][] coverBoard, int hBase) {
for (int c = COVER_START_INDEX; c <= BOARD_SIZE; c++) {
for (int n = COVER_START_INDEX; n <= BOARD_SIZE; n++, hBase++) {
for (int r1 = COVER_START_INDEX; r1 <= BOARD_SIZE; r1++) {
int index = getIndex(r1, c, n);
coverBoard[index][hBase] = true;
}
}
}
return hBase;
}
private int checkRowConstraint(boolean[][] coverBoard, int hBase) {
for (int r = COVER_START_INDEX; r <= BOARD_SIZE; r++) {
for (int n = COVER_START_INDEX; n <= BOARD_SIZE; n++, hBase++) {
for (int c1 = COVER_START_INDEX; c1 <= BOARD_SIZE; c1++) {
int index = getIndex(r, c1, n);
coverBoard[index][hBase] = true;
}
}
}
return hBase;
}
private int checkCellConstraint(boolean[][] coverBoard, int hBase) {
for (int r = COVER_START_INDEX; r <= BOARD_SIZE; r++) {
for (int c = COVER_START_INDEX; c <= BOARD_SIZE; c++, hBase++) {
for (int n = COVER_START_INDEX; n <= BOARD_SIZE; n++) {
int index = getIndex(r, c, n);
coverBoard[index][hBase] = true;
}
}
}
return hBase;
}
private boolean[][] initializeExactCoverBoard(int[][] board) {
boolean[][] R = createExactCoverBoard();
boolean[][] coverBoard = createExactCoverBoard();
for (int i = COVER_START_INDEX; i <= BOARD_SIZE; i++) {
for (int j = COVER_START_INDEX; j <= BOARD_SIZE; j++) {
int n = board[i - 1][j - 1];
if (n != NO_VALUE) {
for (int num = MIN_VALUE; num <= MAX_VALUE; num++) {
if (num != n) {
Arrays.fill(R[getIndex(i, j, num)], false);
Arrays.fill(coverBoard[getIndex(i, j, num)], false);
}
}
}
}
}
return R;
return coverBoard;
}
}