Check max Hamming weight in the other direction.

[matchsticks-search.git] / main.c

diff --git a/main.c b/main.c
index 6f0df725949c9b26fccb613768f74c283bc9e591..3c1b123b2e71155b058bdc34d45f058f6db592f9 100644 (file)
--- a/main.c
+++ b/main.c
@@ -86,6 +86,9 @@ static double best;
 static glp_prob *best_prob;
 static AdjWord *best_adjmatrix;
 
+static int n_over_best;
+static int *weight;
+
 static unsigned printcounter;
 
 static AdjWord *xalloc_adjmatrix(void) {
@@ -96,6 +99,9 @@ static void prep(void) {
   adjall = ~((~(AdjWord)0) << m);
   adjmatrix = xalloc_adjmatrix();
   glp_term_out(GLP_OFF);
+  n_over_best = n / best;
+  weight = (int *)malloc(m*sizeof(int));
+  for (int j = 0; j < m; j++) weight[j] = 0;
 }
 
 static AdjWord one_adj_bit(int bitnum) {
@@ -300,6 +306,7 @@ static void optimise(int doprint) {
   HAVE_PRINTED;
 
   best = got;
+  n_over_best = n / best;
 
   if (best_prob) glp_delete_prob(best_prob);
   best_prob = prob;
@@ -331,9 +338,20 @@ static void iterate_recurse(int i, AdjWord min) {
       goto again;
     if (i == 0 && (adjmatrix[i] & (1+adjmatrix[i])))
       goto again;
+    for (int j = 0; j < m; j++)
+      if (adjmatrix[i] & (1 << j))
+        weight[j]++;
+    for (int j = 0; j < m; j++)
+      if (weight[j] >= n_over_best)
+        goto takeout;
 
     iterate_recurse(i+1, adjmatrix[i]);
 
+   takeout:
+    for (int j = 0; j < m; j++)
+      if (adjmatrix[i] & (1 << j))
+        weight[j]--;
+
   again:
     if (adjmatrix[i] == adjall)
       return;