CDE

Task/Combinations/JavaScript/combinations-1.js

@@ -0,0 +1,18 @@
+function bitprint(u) {
+  var s="";
+  for (var n=0; u; ++n, u>>=1)
+    if (u&1) s+=n+" ";
+  return s;
+}
+function bitcount(u) {
+  for (var n=0; u; ++n, u=u&(u-1));
+  return n;
+}
+function comb(c,n) {
+  var s=[];
+  for (var u=0; u<1<<n; u++)
+    if (bitcount(u)==c)
+      s.push(bitprint(u))
+  return s.sort();
+}
+comb(3,5)

Task/Combinations/JavaScript/combinations-2.js

@@ -0,0 +1,25 @@
+function combinations(arr, k){
+    var i,
+    subI,
+    ret = [],
+    sub,
+    next;
+    for(i = 0; i < arr.length; i++){
+        if(k === 1){
+            ret.push( [ arr[i] ] );
+        }else{
+            sub = combinations(arr.slice(i+1, arr.length), k-1);
+            for(subI = 0; subI < sub.length; subI++ ){
+                next = sub[subI];
+                next.unshift(arr[i]);
+                ret.push( next );
+            }
+        }
+    }
+    return ret;
+}
+combinations([0,1,2,3,4], 3);
+// produces: [[0, 1, 2], [0, 1, 3], [0, 1, 4], [0, 2, 3], [0, 2, 4], [0, 3, 4], [1, 2, 3], [1, 2, 4], [1, 3, 4], [2, 3, 4]]
+
+combinations(["Crosby", "Stills", "Nash", "Young"], 3);
+// produces: [["Crosby", "Stills", "Nash"], ["Crosby", "Stills", "Young"], ["Crosby", "Nash", "Young"], ["Stills", "Nash", "Young"]]