From 5c15e6abda97c19829d5b2b348b422f3857b42f7 Mon Sep 17 00:00:00 2001
From: Robert Vollmert <rvollmert@gmx.net>
Date: Fri, 13 Nov 2009 23:34:11 +0100
Subject: Implement weighted choice from array.

---
 crawl-ref/source/random-weight.h | 22 ++++++++++++++++++++++
 1 file changed, 22 insertions(+)
 create mode 100644 crawl-ref/source/random-weight.h

(limited to 'crawl-ref/source/random-weight.h')

diff --git a/crawl-ref/source/random-weight.h b/crawl-ref/source/random-weight.h
new file mode 100644
index 0000000000..7b9995520f
--- /dev/null
+++ b/crawl-ref/source/random-weight.h
@@ -0,0 +1,22 @@
+#ifndef RANDOM_WEIGHT_H
+#define RANDOM_WEIGHT_H
+
+template <typename T>
+T* random_choose_weighted(std::vector<std::pair<T, int> > choices)
+{
+    int total = 0;
+    for (unsigned int i = 0; i < choices.size(); i++)
+        total += choices[i].second;
+    int r = random2(total);
+    int sum = 0;
+    for (unsigned int i = 0; i < choices.size(); i++)
+    {
+        sum += choices[i].second;
+        if (sum > r)
+            return (&choices[i].first);
+    }
+    return (NULL);
+}
+
+#endif
+
-- 
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