Time for an 2014 update…

Task/Josephus-problem/AWK/josephus-problem.awk

@@ -0,0 +1,37 @@
+# syntax: GAWK -f JOSEPHUS_PROBLEM.AWK
+# converted from PL/I
+BEGIN {
+    main(5,2,1)
+    main(41,3,1)
+    main(41,3,3)
+    exit(0)
+}
+function main(n,k,s,  dead,errors,found,i,killed,nn,p,survived) {
+# n - number of prisoners
+# k - kill every k'th prisoner
+# s - number of survivors
+    printf("\nn=%d k=%d s=%d\n",n,k,s) # show arguments
+    if (s > n) { print("s>n"); errors++ }
+    if (k <= 0) { print("k<=0"); errors++ }
+    if (errors > 0) { return(0) }
+    nn = n                             # wrap around boundary
+    p = -1                             # start here
+    while (n != s) {                   # until survivor count is met
+      found = 0                        # start looking
+      while (found != k) {             # until we have the k-th prisoner
+        if (++p == nn) { p = 0 }       # wrap around
+        if (dead[p] != 1) { found++ }  # if prisoner is alive increment found
+      }
+      dead[p] = 1                      # kill the unlucky one
+      killed = killed p " "            # build killed list
+      n--                              # reduce size of circle
+    }
+    for (i=0; i<=nn-1; i++) {
+      if (dead[i] != 1) {
+        survived = survived i " "      # build survivor list
+      }
+    }
+    printf("killed: %s\n",killed)
+    printf("survived: %s\n",survived)
+    return(1)
+}

Task/Josephus-problem/D/josephus-problem.d

@@ -7,7 +7,7 @@ T pop(T)(ref T[] items, in size_t i) pure {
     return aux;
 }
 
-string josephus(in int n, in int k) /*pure*/ {
+string josephus(in int n, in int k) pure {
     auto p = n.iota.array;
     int i;
     int[] seq;

Task/Josephus-problem/Forth/josephus-problem.fth

@@ -0,0 +1 @@
+: josephus  0 1 begin dup 41 <= while  swap 3 + over mod swap  1+ repeat drop ;

Task/Josephus-problem/Groovy/josephus-problem.groovy

@@ -0,0 +1,36 @@
+int[] Josephus (int size, int kill, int survivors) {
+    // init user pool
+    def users = new int[size];
+
+    // give initial values such that [0] = 1 (first person) [1] = 2 (second person) etc
+    users.eachWithIndex() {obj, i -> users[i] = i + 1};
+
+    // keep track of which person we are on (ranging from 1 to kill)
+    def person = 1;
+
+    // keep going until we have the desired number of survivors
+    while (users.size() > survivors)
+    {
+        // for each person, if they are the kill'th person, set them to -1 to show eliminated
+        users.eachWithIndex() {obj, i ->
+            if (person++ % kill == 0) {
+                users[i] = -1;
+            }
+
+            // if person overflowed kill then reset back to 1
+            if (person > kill) {person = 1;}
+        }
+
+        // clear out all eliminated persons
+        users = users.findAll{w -> w >= 0};
+    }
+
+    // resulting set is the safe positions
+    return users;
+}
+
+// Run some test cases
+
+println "Final survivor for n = 10201 and k = 17: " + Josephus(10201,17,1)[0];
+
+println "4 safe spots for n = 10201 and k = 17: " + Josephus(10201,17,4);

Task/Josephus-problem/Lua/josephus-problem.lua

@@ -0,0 +1,24 @@
+function josephus(n, k, m)
+    local positions={}
+    for i=1,n do
+        table.insert(positions, i-1)
+    end
+    local i,j=1,1
+    local s='Execution order: '
+    while #positions>m do
+        if j==k then
+            s=s .. positions[i] .. ', '
+            table.remove(positions, i)
+            i=i-1
+        end
+        i=i+1
+        j=j+1
+        if i>#positions then i=1 end
+        if j>k then j=1 end
+    end
+    print(s:sub(1,#s-2) .. '.')
+    local s='Survivors: '
+    for _,v in pairs(positions) do s=s .. v .. ', ' end
+    print(s:sub(1,#s-2) .. '.')
+end
+josephus(41,3, 1)

Task/Josephus-problem/REBOL/josephus-problem-1.rebol

@@ -0,0 +1,13 @@
+Rebol []
+
+execute: func [death-list [block!] kill [integer!]] [
+    assert [not empty? death-list]
+    until [
+        loop kill - 1 [append death-list take death-list]
+        (1 == length? remove death-list)
+    ]
+]
+
+prisoner: [] for n 0 40 1 [append prisoner n]
+execute prisoner 3
+print ["Prisoner" prisoner "survived"]

Task/Josephus-problem/REBOL/josephus-problem-2.rebol

@@ -0,0 +1,3 @@
+for-the-chop: [Joe Jack William Averell Rantanplan]
+execute for-the-chop 2
+print [for-the-chop "survived"]