The check for solvable puzzles didn't use all squares. This fixes bug #911484. Now uses rand() instead of current_tick for randomizing.

git-svn-id: svn://svn.rockbox.org/rockbox/trunk@4864 a1c6a512-1295-4272-9138-f99709370657

1 files changed, 9 insertions, 4 deletions

diff --git a/apps/plugins/sliding_puzzle.c b/apps/plugins/sliding_puzzle.c
index 12c7a9a..423ab7f 100644
--- a/apps/plugins/sliding_puzzle.c
+++ b/apps/plugins/sliding_puzzle.c
@@ -180,7 +180,7 @@ static void puzzle_init(void)
     
     /* shuffle spots */
     for (i=19; i>=0; i--) {
-        r = (*rb->current_tick % (i+1));
+        r = (rb->rand() % (i+1));
     
         temp = spots[r];
         spots[r] = spots[i];
@@ -192,11 +192,16 @@ static void puzzle_init(void)
     
     /* test if the puzzle is solvable */
     for (i=0; i<20; i++)
-    tsp[i] = spots[i];
+        tsp[i] = spots[i];
     r=0;
+
+    /* First, check if the problem has even or odd parity,
+       depending on where the empty square is */
     if (((4-hole%5) + (3-hole/5))%2 == 1)
-    ++r;
-    for (i=0; i<15; i++) {
+        ++r;
+
+    /* Now check how many swaps we need to solve it */
+    for (i=0; i<19; i++) {
         while (tsp[i] != (i+1)) {
             temp = tsp[i];
             tsp[i] = tsp[temp-1];