A-M baby

Task/Hailstone-sequence/R/hailstone-sequence-1.r

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+### PART 1:
+makeHailstone <- function(n){
+  hseq <- n
+  while (hseq[length(hseq)] > 1){
+    current.value <- hseq[length(hseq)]
+    if (current.value %% 2 == 0){
+      next.value <- current.value / 2
+    } else {
+      next.value <- (3 * current.value) + 1
+    }
+    hseq <- append(hseq, next.value)
+  }
+  return(list(hseq=hseq, seq.length=length(hseq)))
+}
+
+### PART 2:
+twenty.seven <- makeHailstone(27)
+twenty.seven$hseq
+twenty.seven$seq.length
+
+### PART 3:
+max.length <- 0;  lower.bound <- 1;  upper.bound <- 100000
+
+for (index in lower.bound:upper.bound){
+  current.hseq <- makeHailstone(index)
+  if (current.hseq$seq.length > max.length){
+    max.length <- current.hseq$seq.length
+    max.index  <- index
+  }
+}
+
+cat("Between ", lower.bound, " and ", upper.bound, ", the input of ",
+    max.index, " gives the longest hailstone sequence, which has length ",
+    max.length, ". \n", sep="")

Task/Hailstone-sequence/R/hailstone-sequence-2.r

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+> twenty.seven$hseq
+  [1]   27   82   41  124   62   31   94   47  142   71  214  107  322  161  484
+ [16]  242  121  364  182   91  274  137  412  206  103  310  155  466  233  700
+ [31]  350  175  526  263  790  395 1186  593 1780  890  445 1336  668  334  167
+ [46]  502  251  754  377 1132  566  283  850  425 1276  638  319  958  479 1438
+ [61]  719 2158 1079 3238 1619 4858 2429 7288 3644 1822  911 2734 1367 4102 2051
+ [76] 6154 3077 9232 4616 2308 1154  577 1732  866  433 1300  650  325  976  488
+ [91]  244  122   61  184   92   46   23   70   35  106   53  160   80   40   20
+[106]   10    5   16    8    4    2    1
+
+> twenty.seven$seq.length
+[1] 112
+
+Between 1 and 1e+05, the input of 77031 gives the longest hailstone sequence,
+which has length 351.