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Use uint16_t instead of struct for cell state

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- Bits 0-8 are the possible values
- Bits 9-12 is the concrete value
- Bit 15 is 1 if the cell is determined
This commit is contained in:
Camden Dixie O'Brien
2022-11-24 00:37:48 +00:00
parent 4a2cfb392f
commit f51e9a06b0
3 changed files with 49 additions and 41 deletions
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48
sud.c
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@@ -24,20 +24,22 @@
#define MAX_FILL_ATTEMPTS 32
static void initposs(struct sudoku *sud)
#define CELLINIT 0x01ff
static void init(struct sudoku *sud)
{
for (unsigned r = 0; r < NDIGITS; ++r) {
for (unsigned c = 0; c < NDIGITS; ++c) {
sud->cells[r][c].det = false;
for (unsigned i = 0; i < NDIGITS; ++i)
sud->cells[r][c].pvals[i] = true;
sud->cells[r][c] = CELLINIT;
}
}
}
bool load(struct sudoku *sud, const char *ptr)
{
initposs(sud);
init(sud);
for (unsigned i = 0; i < NCELLS; ++i) {
if (ptr[i] == '0')
continue;
@@ -53,18 +55,20 @@ enum update_res update(struct sudoku *sud, unsigned r, unsigned c, unsigned val)
unsigned tr, tc;
assert(val < NDIGITS);
const uint16_t clearmask = ~(1 << val);
/* Update possible values of cells in same column. */
for (tr = 0; tr < NDIGITS; ++tr) {
if (tr == r || sud->cells[tr][c].det)
if (tr == r || DET(sud->cells[tr][c]))
continue;
sud->cells[tr][c].pvals[val] = false;
sud->cells[tr][c] &= clearmask;
}
/* Update possible values of cells in same row. */
for (tc = 0; tc < NDIGITS; ++tc) {
if (tc == c || sud->cells[r][tc].det)
if (tc == c || DET(sud->cells[r][tc]))
continue;
sud->cells[r][tc].pvals[val] = false;
sud->cells[r][tc] &= clearmask;
}
/* Update possible values of cells in same segment. */
@@ -72,15 +76,15 @@ enum update_res update(struct sudoku *sud, unsigned r, unsigned c, unsigned val)
const unsigned segc0 = SEGLEN * (c / SEGLEN);
for (tr = segr0; tr < segr0 + SEGLEN; ++tr) {
for (tc = segc0; tc < segc0 + SEGLEN; ++tc) {
if ((tr == r && tc == c) || sud->cells[tr][tc].det)
if ((tr == r && tc == c) || DET(sud->cells[tr][tc]))
continue;
sud->cells[tr][tc].pvals[val] = false;
sud->cells[tr][tc] &= clearmask;
}
}
/* Set the cell's value. */
sud->cells[r][c].det = true;
sud->cells[r][c].val = val;
sud->cells[r][c] |= DETMASK;
sud->cells[r][c] |= val << VALSHIFT;
return OK;
}
@@ -103,8 +107,8 @@ void print(const struct sudoku *sud)
if (c != 0 && c % SEGLEN == 0)
fputs("| ", stdout);
if (sud->cells[r][c].det)
printf("%u ", sud->cells[r][c].val + 1);
if (DET(sud->cells[r][c]))
printf("%u ", VAL(sud->cells[r][c]) + 1);
else
fputs(" ", stdout);
}
@@ -135,9 +139,9 @@ enum check_res check(const struct sudoku *sud)
for (r = 0; r < NDIGITS; ++r) {
zerocounts(digitcounts);
for (c = 0; c < NDIGITS; ++c) {
if (!sud->cells[r][c].det)
if (!DET(sud->cells[r][c]))
return INCOMPLETE;
++digitcounts[sud->cells[r][c].val];
++digitcounts[VAL(sud->cells[r][c])];
}
if (!checkcounts(digitcounts))
return INCORRECT;
@@ -147,9 +151,9 @@ enum check_res check(const struct sudoku *sud)
for (c = 0; c < NDIGITS; ++c) {
zerocounts(digitcounts);
for (r = 0; r < NDIGITS; ++r) {
if (!sud->cells[r][c].det)
if (!DET(sud->cells[r][c]))
return INCOMPLETE;
++digitcounts[sud->cells[r][c].val];
++digitcounts[VAL(sud->cells[r][c])];
}
if (!checkcounts(digitcounts))
return INCORRECT;
@@ -161,9 +165,9 @@ enum check_res check(const struct sudoku *sud)
for (j = 0; j < NDIGITS; ++j) {
r = 3 * (i / 3) + j / 3;
c = 3 * (i % 3) + j % 3;
if (!sud->cells[r][c].det)
if (!DET(sud->cells[r][c]))
return INCOMPLETE;
++digitcounts[sud->cells[r][c].val];
++digitcounts[VAL(sud->cells[r][c])];
}
if (!checkcounts(digitcounts))
return INCORRECT;
@@ -177,7 +181,7 @@ bool filled(const struct sudoku *sud)
{
for (unsigned r = 0; r < NDIGITS; ++r) {
for (unsigned c = 0; c < NDIGITS; ++c) {
if (!sud->cells[r][c].det)
if (!(DET(sud->cells[r][c])))
return false;
}
}