forked from len0rd/rockbox
09aa8de52c
This brings the puzzles source in sync with Simon's branch, commit fd304c5 (from March 2024), with some added Rockbox-specific compatibility changes: https://www.franklinwei.com/git/puzzles/commit/?h=rockbox-devel&id=516830d9d76bdfe64fe5ccf2a9b59c33f5c7c078 There are quite a lot of backend changes, including a new "Mosaic" puzzle. In addition, some new frontend changes were necessary: - New "Preferences" menu to access the user preferences system. - Enabled spacebar input for several games. Change-Id: I94c7df674089c92f32d5f07025f6a1059068af1e
73 lines
1.3 KiB
C
73 lines
1.3 KiB
C
#include <assert.h>
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#include <string.h>
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#include "puzzles.h"
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/* horrific and doesn't check overflow. */
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static long factx(long x, long y)
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{
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long acc = 1, i;
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for (i = y; i <= x; i++)
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acc *= i;
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return acc;
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}
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void reset_combi(combi_ctx *combi)
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{
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int i;
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combi->nleft = combi->total;
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for (i = 0; i < combi->r; i++)
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combi->a[i] = i;
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}
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combi_ctx *new_combi(int r, int n)
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{
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long nfr, nrf;
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combi_ctx *combi;
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assert(r <= n);
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assert(n >= 1);
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combi = snew(combi_ctx);
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memset(combi, 0, sizeof(combi_ctx));
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combi->r = r;
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combi->n = n;
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combi->a = snewn(r, int);
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memset(combi->a, 0, r * sizeof(int));
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nfr = factx(n, r+1);
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nrf = factx(n-r, 1);
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combi->total = (int)(nfr / nrf);
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reset_combi(combi);
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return combi;
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}
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/* returns NULL when we're done otherwise returns input. */
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combi_ctx *next_combi(combi_ctx *combi)
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{
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int i = combi->r - 1, j;
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if (combi->nleft == combi->total)
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goto done;
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else if (combi->nleft <= 0)
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return NULL;
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while (combi->a[i] == combi->n - combi->r + i)
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i--;
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combi->a[i] += 1;
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for (j = i+1; j < combi->r; j++)
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combi->a[j] = combi->a[i] + j - i;
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done:
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combi->nleft--;
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return combi;
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}
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void free_combi(combi_ctx *combi)
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{
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sfree(combi->a);
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sfree(combi);
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}
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