- Added guest contributions by Laurent Rosenfeld.

8 files changed, 182 insertions, 0 deletions

diff --git a/challenge-137/laurent-rosenfeld/awk/ch-2.awk b/challenge-137/laurent-rosenfeld/awk/ch-2.awk
new file mode 100644
index 0000000000..7dac9b2864
--- /dev/null
+++ b/challenge-137/laurent-rosenfeld/awk/ch-2.awk
@@ -0,0 +1,23 @@
+#!/usr/bin/awk
+
+function reverse (num) {
+    rev = ""
+    len = length(num)
+    for (i = len; i > 0; i--) {
+        rev = rev substr(num, i, 1);
+    }
+    return rev
+}
+function is_lychrel(n) {
+    for (i = 1; i <= 5; i++) {
+        if (n > 10000000) {
+            return "is a Lychrel candidate. Reached the 1e7 limit"
+        }
+        rev = reverse(n)
+        # print n, rev
+        if (n == rev) { return 0 }
+        n += rev
+    }
+    return "is a lychrel candidate (made 500 iterations)"
+}
+/[0-9]+/ { print $0, " -> ", is_lychrel($0) }
diff --git a/challenge-137/laurent-rosenfeld/bc/ch-2.bc b/challenge-137/laurent-rosenfeld/bc/ch-2.bc
new file mode 100644
index 0000000000..fee4dd6f55
--- /dev/null
+++ b/challenge-137/laurent-rosenfeld/bc/ch-2.bc
@@ -0,0 +1,31 @@
+define reverse (n) {
+    rev = 0
+    while (n > 0) {
+        rev *= 10
+        rev += n % 10
+        n /= 10
+    }
+    return (rev)
+}
+
+
+define is_lychrel(n) {
+    for (i = 1; i < 500; i++) {
+        if (n >= 10000000) { return -1}
+        rev = reverse(n)
+        /* print n, " ", rev, "\n" */
+        if (n == rev) {return 0;}
+        n += rev
+    }
+    return -1
+}
+
+while (1) {
+    n = read ()
+    if (is_lychrel (n) == -1) {
+        print n, " Lychrel candidate", "\n"
+    } else {
+        print n, " ", 0, "\n"
+        }
+}
+quit
diff --git a/challenge-137/laurent-rosenfeld/c/ch-2.c b/challenge-137/laurent-rosenfeld/c/ch-2.c
new file mode 100644
index 0000000000..3ab090b712
--- /dev/null
+++ b/challenge-137/laurent-rosenfeld/c/ch-2.c
@@ -0,0 +1,42 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#define MAX_ITER 500
+#define MAX_VAL 10000000
+#define NB_TESTS 6
+
+void reverse_str(char* str) {
+    int len, tmp;
+    len = strlen(str);
+    for (int i = 0; i < len/2; i++) {
+        tmp = str[i];
+        str[i] = str[len - i - 1];
+        str[len - i - 1] = tmp;
+    }
+}
+
+const char* lychrel (int n) {
+    char out[20];
+    for (int k = 1; k <= MAX_ITER; k++) {
+        if (n > MAX_VAL) {
+            return "is a Lychrel candidate. Reached the 1e7 limit";
+        }
+        char to_str[20];
+        char rev[20];
+        sprintf(to_str, "%d", n);
+        strcpy(rev, to_str);
+        reverse_str(rev);
+        if (strcmp(to_str, rev) == 0) {
+            return "0";
+        }
+        n += atoi(rev);
+    }
+    return "is a Lychrel candidate. Reached 500 iterations";
+}
+
+int main() {
+    int tests[NB_TESTS] = { 10, 20, 30, 50, 100, 196};
+    for (int i = 0; i < NB_TESTS; i++) {
+        printf("%d -> %s\n", tests[i], lychrel(tests[i]));
+    }
+}
diff --git a/challenge-137/laurent-rosenfeld/julia/ch-1.jl b/challenge-137/laurent-rosenfeld/julia/ch-1.jl
new file mode 100644
index 0000000000..4ea2aff39a
--- /dev/null
+++ b/challenge-137/laurent-rosenfeld/julia/ch-1.jl
@@ -0,0 +1,16 @@
+function is_lychrel(n)
+    m = n
+    for k = 1:500
+        if (n > 10_000_000)
+            return "$m is a Lychrel candidate. Reached the 1e7 limit"
+        end
+        rev = parse(Int64, reverse(string(n)))
+        if (n == rev) return 0 end
+        n += rev
+    end
+    return "$m is a lychrel candidate (made 500 iterations)";
+end
+
+for test in [10, 20, 30, 50, 100, 196]
+    println("$test ->  $(is_lychrel(test))")
+end
diff --git a/challenge-137/laurent-rosenfeld/lua/ch-2.lua b/challenge-137/laurent-rosenfeld/lua/ch-2.lua
new file mode 100644
index 0000000000..60ab8f2e76
--- /dev/null
+++ b/challenge-137/laurent-rosenfeld/lua/ch-2.lua
@@ -0,0 +1,16 @@
+function is_lychrel(n)
+    m = n
+    for k =1, 500 do
+        if n > 10000000 then
+            return string.format("%s is a Lychrel candidate. Reached the 1e7 limit", m)
+        end
+        rev = tonumber(string.reverse(tostring(n)))
+        if n == rev then return 0 end
+        n = n + rev
+    end
+    return string.format("%s is a lychrel candidate (made 500 iterations)", m);
+end
+
+for key, test in ipairs({10, 20, 30, 50, 100, 196}) do
+    print(test, " -> ", is_lychrel(test))
+end
diff --git a/challenge-137/laurent-rosenfeld/python/ch-2.py b/challenge-137/laurent-rosenfeld/python/ch-2.py
new file mode 100644
index 0000000000..2442d978c8
--- /dev/null
+++ b/challenge-137/laurent-rosenfeld/python/ch-2.py
@@ -0,0 +1,18 @@
+#!/usr/bin/python3
+
+def is_lychrel(m):
+    n = m
+    for i in range(500):
+        j = int(str(n)[::-1])
+        if j == n:
+            return 0
+        n += j
+        if n > 10000000:
+            return "n is a lychrel candidate. Reached the 1e7 limit."
+    return "n is a lychrel candidate. Made 500 iterations."
+
+for test in range(10, 20):
+    print(test, " -> ", is_lychrel(test))
+
+for test in 10, 20, 30, 50, 100, 196:
+    print(test, " -> ", is_lychrel(test))
diff --git a/challenge-137/laurent-rosenfeld/ruby/ch-2.rb b/challenge-137/laurent-rosenfeld/ruby/ch-2.rb
new file mode 100644
index 0000000000..1baf7c046c
--- /dev/null
+++ b/challenge-137/laurent-rosenfeld/ruby/ch-2.rb
@@ -0,0 +1,20 @@
+#! /usr/bin/ruby
+
+def is_lychrel(m)
+    n = m
+    for k in 1..500
+        j = n.to_s.reverse.to_i
+        if j == n then
+            return 0
+        end
+        n += j
+        if n > 10000000 then
+            return "#{m} is  a Lychrel candidate (reached the 1e7 limit)"
+        end
+    end
+    return "#{m} is a lychrel candidate (made 500 iterations)"
+end
+
+for test in [10, 20, 30, 50, 100, 196]
+    print  "#{test} -> ", is_lychrel(test), "\n"
+end
diff --git a/challenge-137/laurent-rosenfeld/rust/ch-2.rs b/challenge-137/laurent-rosenfeld/rust/ch-2.rs
new file mode 100644
index 0000000000..60ab8f2e76
--- /dev/null
+++ b/challenge-137/laurent-rosenfeld/rust/ch-2.rs
@@ -0,0 +1,16 @@
+function is_lychrel(n)
+    m = n
+    for k =1, 500 do
+        if n > 10000000 then
+            return string.format("%s is a Lychrel candidate. Reached the 1e7 limit", m)
+        end
+        rev = tonumber(string.reverse(tostring(n)))
+        if n == rev then return 0 end
+        n = n + rev
+    end
+    return string.format("%s is a lychrel candidate (made 500 iterations)", m);
+end
+
+for key, test in ipairs({10, 20, 30, 50, 100, 196}) do
+    print(test, " -> ", is_lychrel(test))
+end