Data commit

Task/Hofstadter-Q-sequence/Dart/hofstadter-q-sequence-1.dart

@@ -0,0 +1,8 @@
+int Q(int n) => n>2 ? Q(n-Q(n-1))+Q(n-Q(n-2)) : 1;
+
+main() {
+  for(int i=1;i<=10;i++) {
+    print("Q($i)=${Q(i)}");
+  }
+  print("Q(1000)=${Q(1000)}");
+}

Task/Hofstadter-Q-sequence/Dart/hofstadter-q-sequence-2.dart

@@ -0,0 +1,42 @@
+class Q {
+  Map<int,int> _table;
+
+  Q() {
+    _table=new Map<int,int>();
+    _table[1]=1;
+    _table[2]=1;
+  }
+
+  int q(int n) {
+    // if the cache is not filled until n-1, fill it starting with the lowest entries first
+    // this avoids doing a recursion from n to 2 (e.g. if you call q(1000000) first)
+    // this doesn't happen in the  tasks calls since the cache is filled ascending
+    if(_table[n-1]==null) {
+      for(int i=_table.length;i<n;i++) {
+		q(i);
+	  }
+    }
+    if(_table[n]==null) {
+      _table[n]=q(n-q(n-1))+q(n-q(n-2));
+    }
+
+    return _table[n];
+  }
+}
+
+main() {
+  Q q=new Q();
+
+  for(int i=1;i<=10;i++) {
+    print("Q($i)=${q.q(i)}");
+  }
+  print("Q(1000)=${q.q(1000)}");
+
+  int count=0;
+  for(int i=2;i<=100000;i++) {
+    if(q.q(i)<q.q(i-1)) {
+      count++;
+    }
+  }
+  print("value is smaller than previous $count times");
+}

Task/Hofstadter-Q-sequence/Dart/hofstadter-q-sequence-3.dart

@@ -0,0 +1,17 @@
+main() {
+  List<int> q=new List<int>(100001);
+  q[1]=q[2]=1;
+
+  int count=0;
+  for(int i=3;i<q.length;i++) {
+    q[i]=q[i-q[i-1]]+q[i-q[i-2]];
+    if(q[i]<q[i-1]) {
+      count++;
+    }
+  }
+  for(int i=1;i<=10;i++) {
+    print("Q($i)=${q[i]}");
+  }
+  print("Q(1000)=${q[1000]}");
+  print("value is smaller than previous $count times");
+}