Add D solution to challenge 119

2 files changed, 94 insertions, 0 deletions

diff --git a/challenge-119/paulo-custodio/d/ch_1.d b/challenge-119/paulo-custodio/d/ch_1.d
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+/*
+Challenge 119
+
+TASK #1 - Swap Nibbles
+Submitted by: Mohammad S Anwar
+You are given a positive integer $N.
+
+Write a script to swap the two nibbles of the binary representation of the
+given number and print the decimal number of the new binary representation.
+
+A nibble is a four-bit aggregation, or half an octet.
+
+To keep the task simple, we only allow integer less than or equal to 255.
+
+Example
+Input: $N = 101
+Output: 86
+
+Binary representation of decimal 101 is 1100101 or as 2 nibbles (0110)(0101).
+The swapped nibbles would be (0101)(0110) same as decimal 86.
+
+Input: $N = 18
+Output: 33
+
+Binary representation of decimal 18 is 10010 or as 2 nibbles (0001)(0010).
+The swapped nibbles would be (0010)(0001) same as decimal 33.
+*/
+
+import std.stdio;
+import std.conv;
+
+void main(string[] args) {
+    auto n = to!int(args[1]);
+    n = ((n >> 4) & 0x0f) | ((n << 4) & 0xf0);
+    writeln(n);
+}
diff --git a/challenge-119/paulo-custodio/d/ch_2.d b/challenge-119/paulo-custodio/d/ch_2.d
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+/*
+Challenge 119
+
+TASK #2 - Sequence without 1-on-1
+Submitted by: Cheok-Yin Fung
+Write a script to generate sequence starting at 1. Consider the increasing
+sequence of integers which contain only 1's, 2's and 3's, and do not have any
+doublets of 1's like below. Please accept a positive integer $N and print the
+$Nth term in the generated sequence.
+
+1, 2, 3, 12, 13, 21, 22, 23, 31, 32, 33, 121, 122, 123, 131, ...
+
+Example
+Input: $N = 5
+Output: 13
+
+Input: $N = 10
+Output: 32
+
+Input: $N = 60
+Output: 2223
+*/
+
+import std.stdio;
+import std.conv;
+
+bool num_ok(int n) {
+    int last_digit, digit;
+
+    if (n <= 0)
+        return false;
+    while (n > 0) {
+        last_digit = digit;
+        digit = n % 10;
+        n /= 10;
+        if (digit < 1 || digit > 3 || (digit == 1 && last_digit == 1))
+            return false;
+    }
+    return true;
+}
+
+int next_seq(int seq) {
+    while (1) {
+        seq++;
+        if (num_ok(seq))
+            return seq;
+    }
+}
+
+void main(string[] args) {
+    auto num = to!int(args[1]);
+
+    int seq = 0;
+    foreach (int i; 0 .. num)
+        seq = next_seq(seq);
+
+    writeln(seq);
+}