Add challenge-160

4 files changed, 214 insertions, 24 deletions

diff --git a/challenge-160/andinus/README b/challenge-160/andinus/README
index bd1dd6e3ce..cb7306aa47 100644
--- a/challenge-160/andinus/README
+++ b/challenge-160/andinus/README
@@ -1,51 +1,113 @@
                             ━━━━━━━━━━━━━━━
-                             CHALLENGE 135
+                             CHALLENGE 160
 
                                 Andinus
                             ━━━━━━━━━━━━━━━
 
 
-                               2021-10-22
+                               2022-04-12
 
 
 
 
 
-Task 1 - Middle 3-digits
-════════════════════════
+Task 1 - Four Is Magic
+══════════════════════
 
-  You are given an integer.
+  You are given a positive number, $n < 10.
 
-  Write a script find out the middle 3-digits of the given integer, if
-  possible otherwise throw sensible error.
+  Write a script to generate english text sequence starting with the
+  English cardinal representation of the given number, the word ‘is’ and
+  then the English cardinal representation of the count of characters
+  that made up the first word, followed by a comma. Continue until you
+  reach four.
 
   ┌────
-  │ Input: $n = 1234567
-  │ Output: 345
+  │ Input: $n = 5
+  │ Output: Five is four, four is magic.
   │
-  │ Input: $n = -123
-  │ Output: 123
+  │ Input: $n = 7
+  │ Output: Seven is five, five is four, four is magic.
   │
-  │ Input: $n = 1
-  │ Output: too short
+  │ Input: $n = 6
+  │ Output: Six is three, three is five, five is four, four is magic.
+  └────
+
+
+Raku
+────
+
+  Take a positive number, less than 10 as input from MAIN. Then we
+  define an array that holds the string representation of integers. The
+  `multi sub' `four-is-magic' is called on the input. It runs
+  recursively until `4' is called.
+
+  `.tc' is called on the result to make the first character uppercase.
+
+  ┌────
+  │ unit sub MAIN(
+  │     UInt $n where * < 10, #= positive number, less than 10
+  │ );
+  │
+  │ my @num-to-str = <zero one two three four five six seven eight nine>;
+  │
+  │ multi sub four-is-magic(4 --> Str) {
+  │     return "four is magic.";
+  │ }
+  │
+  │ multi sub four-is-magic(Int $n where * < 10 --> Str) {
+  │     my $n-str = @num-to-str[$n];
+  │     return "$n-str is { @num-to-str[$n-str.chars] }, " ~ four-is-magic($n-str.chars);
+  │ }
   │
-  │ Input: $n = 10
-  │ Output: even number of digits
+  │ put four-is-magic($n).tc;
+  └────
+
+
+Task 2 - Equilibrium Index
+══════════════════════════
+
+  You are give an array of integers, @n.
+
+  Write a script to find out the Equilibrium Index of the given array,
+  if found.
+
+        For an array A consisting n elements, index i is an
+        equilibrium index if the sum of elements of subarray
+        A[0…i-1] is equal to the sum of elements of subarray
+        A[i+1…n-1].
+
+  ┌────
+  │ Input: @n = (1, 3, 5, 7, 9)
+  │ Output: 3
+  │
+  │ Input: @n = (1, 2, 3, 4, 5)
+  │ Output: -1 as no Equilibrium Index found.
+  │
+  │ Input: @n = (2, 4, 2)
+  │ Output: 1
   └────
 
 
 Raku
 ────
 
-  Input's absolute value is taken because the sign is meaningless here.
-  To get middle 3-digits we take 3 digits from `$n.chars div 2 - 1'
-  position, `-1' because Arrays are 0-indexed. It's guaranteed that we
-  have odd number of digits so `div 2' will land us on left of middle
-  digit, we just take 3 digits from there.
+  Takes an array of integers as input. Then it loops over the array by
+  index and does as the problem states, takes sum of all elements before
+  the index and compares it with the sum of all elements after the
+  index, if they're equal it prints the index and exits. If there is no
+  Equilibrium Index then it prints -1.
 
   ┌────
-  │ $n = abs $n;
-  │ die "too short" if $n.chars < 3;
-  │ die "even number of digits" if $n.chars %% 2;
-  │ put $n.substr($n.chars div 2 - 1, 3);
+  │ unit sub MAIN(
+  │     *@n, #= array of integers
+  │ );
+  │
+  │ for 0 .. @n.end -> $i {
+  │     if @n[0 .. $i - 1].sum == @n[$i + 1 .. *].sum {
+  │         put $i;
+  │         exit;
+  │     }
+  │ }
+  │ put -1;
   └────
diff --git a/challenge-160/andinus/README.org b/challenge-160/andinus/README.org
new file mode 100644
index 0000000000..d4ae1142fa
--- /dev/null
+++ b/challenge-160/andinus/README.org
@@ -0,0 +1,101 @@
+#+title: Challenge 160
+#+date: 2022-04-12
+#+html_link_up: ../
+#+export_file_name: index
+#+options: toc:nil
+#+setupfile: ~/.emacs.d/org-templates/level-2.org
+
+* Task 1 - Four Is Magic
+
+You are given a positive number, $n < 10.
+
+Write a script to generate english text sequence starting with the
+English cardinal representation of the given number, the word ‘is’ and
+then the English cardinal representation of the count of characters that
+made up the first word, followed by a comma. Continue until you reach
+four.
+
+#+begin_src
+Input: $n = 5
+Output: Five is four, four is magic.
+
+Input: $n = 7
+Output: Seven is five, five is four, four is magic.
+
+Input: $n = 6
+Output: Six is three, three is five, five is four, four is magic.
+#+end_src
+
+** Raku
+
+Take a positive number, less than 10 as input from MAIN. Then we define
+an array that holds the string representation of integers. The ~multi sub~
+~four-is-magic~ is called on the input. It runs recursively until ~4~ is
+called.
+
+~.tc~ is called on the result to make the first character uppercase.
+
+#+begin_src raku
+unit sub MAIN(
+    UInt $n where * < 10, #= positive number, less than 10
+);
+
+my @num-to-str = <zero one two three four five six seven eight nine>;
+
+multi sub four-is-magic(4 --> Str) {
+    return "four is magic.";
+}
+
+multi sub four-is-magic(Int $n where * < 10 --> Str) {
+    my $n-str = @num-to-str[$n];
+    return "$n-str is { @num-to-str[$n-str.chars] }, " ~ four-is-magic($n-str.chars);
+}
+
+put four-is-magic($n).tc;
+#+end_src
+
+* Task 2 - Equilibrium Index
+
+You are give an array of integers, @n.
+
+Write a script to find out the Equilibrium Index of the given array, if
+found.
+
+#+begin_quote
+For an array A consisting n elements, index i is an equilibrium index if
+the sum of elements of subarray A[0…i-1] is equal to the sum of elements
+of subarray A[i+1…n-1].
+#+end_quote
+
+#+begin_src
+Input: @n = (1, 3, 5, 7, 9)
+Output: 3
+
+Input: @n = (1, 2, 3, 4, 5)
+Output: -1 as no Equilibrium Index found.
+
+Input: @n = (2, 4, 2)
+Output: 1
+#+end_src
+
+** Raku
+
+Takes an array of integers as input. Then it loops over the array by
+index and does as the problem states, takes sum of all elements before
+the index and compares it with the sum of all elements after the index,
+if they're equal it prints the index and exits. If there is no
+Equilibrium Index then it prints -1.
+
+#+begin_src raku
+unit sub MAIN(
+    *@n, #= array of integers
+);
+
+for 0 .. @n.end -> $i {
+    if @n[0 .. $i - 1].sum == @n[$i + 1 .. *].sum {
+        put $i;
+        exit;
+    }
+}
+put -1;
+#+end_src
diff --git a/challenge-160/andinus/raku/ch-1.raku b/challenge-160/andinus/raku/ch-1.raku
new file mode 100644
index 0000000000..7ab3307848
--- /dev/null
+++ b/challenge-160/andinus/raku/ch-1.raku
@@ -0,0 +1,16 @@
+unit sub MAIN(
+    UInt $n where * < 10, #= positive number, less than 10
+);
+
+my @num-to-str = <zero one two three four five six seven eight nine>;
+
+multi sub four-is-magic(4 --> Str) {
+    return "four is magic.";
+}
+
+multi sub four-is-magic(Int $n where * < 10 --> Str) {
+    my $n-str = @num-to-str[$n];
+    return "$n-str is { @num-to-str[$n-str.chars] }, " ~ four-is-magic($n-str.chars);
+}
+
+put four-is-magic($n).tc;
diff --git a/challenge-160/andinus/raku/ch-2.raku b/challenge-160/andinus/raku/ch-2.raku
new file mode 100644
index 0000000000..a9045a2712
--- /dev/null
+++ b/challenge-160/andinus/raku/ch-2.raku
@@ -0,0 +1,11 @@
+unit sub MAIN(
+    *@n, #= array of integers
+);
+
+for 0 .. @n.end -> $i {
+    if @n[0 .. $i - 1].sum == @n[$i + 1 .. *].sum {
+        put $i;
+        exit;
+    }
+}
+put -1;