Data commit

Task/Hailstone-sequence/PARI-GP/hailstone-sequence-1.parigp

@@ -0,0 +1,31 @@
+show(n)={
+  my(t=1);
+  while(n>1,
+    print1(n",");
+    n=if(n%2,
+      3*n+1
+    ,
+      n/2
+    );
+    t++
+  );
+  print(1);
+  t
+};
+
+len(n)={
+  my(t=1);
+  while(n>1,
+    if(n%2,
+      t+=2;
+      n+=(n>>1)+1
+    ,
+      t++;
+      n>>=1
+    )
+  );
+  t
+};
+
+show(27)
+r=0;for(n=1,1e5,t=len(n);if(t>r,r=t;ra=n));print(ra"\t"r)

Task/Hailstone-sequence/PARI-GP/hailstone-sequence-2.parigp

@@ -0,0 +1,22 @@
+\\ Get vector with Collatz sequence for the specified starting number.
+\\ Limit vector to the lim length, or less, if 1 (one) term is reached (when lim=0).
+\\ 3/26/2016 aev
+Collatz(n,lim=0)={
+my(c=n,e=0,L=List(n)); if(lim==0, e=1; lim=n*10^6);
+for(i=1,lim, if(c%2==0, c=c/2, c=3*c+1); listput(L,c); if(e&&c==1, break));
+return(Vec(L)); }
+Collatzmax(ns,nf)={
+my(V,vn,mxn=1,mx,im=1);
+print("Search range: ",ns,"..",nf);
+for(i=ns,nf, V=Collatz(i); vn=#V; if(vn>mxn, mxn=vn; im=i); kill(V));
+print("Hailstone/Collatz(",im,") has the longest length = ",mxn);
+}
+
+{
+\\ Required tests:
+print("Required tests:");
+my(Vr,vrn);
+Vr=Collatz(27); vrn=#Vr;
+print("Hailstone/Collatz(27): ",Vr[1..4]," ... ",Vr[vrn-3..vrn],"; length = ",vrn);
+Collatzmax(1,100000);
+}