Author: Andreas Tille <tille@debian.org>
Last-Update: Thu, 23 Jun 2016 09:10:54 +0200
Origin: https://github.com/ekg/multichoose/blob/master/multichoose.h
Description: Provide a needed header file

--- /dev/null
+++ b/src/multichoose.h
@@ -0,0 +1,79 @@
+#ifndef __MULTICHOOSE_H
+#define __MULTICHOOSE_H
+
+/* 
+
+multichoose.h  -- n multichoose k for generic vectors
+
+author: Erik Garrison <erik.garrison@bc.edu>
+last revised: 2010-04-16
+
+Copyright (c) 2010 by Erik Garrison
+
+Permission is hereby granted, free of charge, to any person
+obtaining a copy of this software and associated documentation
+files (the "Software"), to deal in the Software without
+restriction, including without limitation the rights to use,
+copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the
+Software is furnished to do so, subject to the following
+conditions:
+
+The above copyright notice and this permission notice shall be
+included in all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
+OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
+HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
+WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
+OTHER DEALINGS IN THE SOFTWARE.
+
+*/
+
+
+// provides multiset combinations out of the std::vector of objects
+template <class T>
+std::vector< std::vector<T> > multichoose(int k, std::vector<T>& objects) {
+
+    std::vector< std::vector<T> > choices;
+
+    int j,j_1,q,r;
+
+    r = objects.size() - 1;
+
+    // combination indexes
+    std::vector<T*> a, b;
+
+    for (int i=0;i<k;i++) {
+        a.push_back(&objects[0]); b.push_back(&objects[r]);
+    }
+
+    j=k;
+    while(1){
+        std::vector<T> multiset;
+        for(int i=0;i<k;i++)
+            multiset.push_back(*a[i]);
+        choices.push_back(multiset);
+        j=k;
+        do { j--; } while(a[j]==b[j]);
+        if (j<0) break;
+        j_1=j;
+        while(j_1<=k-1){
+            a[j_1]=a[j_1]+1;
+            q=j_1;
+            while(q<k-1) {
+                a[q+1]=a[q];
+                q++;
+            }
+            q++;
+            j_1=q;
+        }
+    }
+    
+    return choices;
+}
+
+#endif