Merge pull request #2340 from Abigail/abigail/week-079

Abigail/week 079

2 files changed, 130 insertions, 0 deletions

diff --git a/challenge-079/abigail/node/ch-1.js b/challenge-079/abigail/node/ch-1.js
new file mode 100644
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+++ b/challenge-079/abigail/node/ch-1.js
@@ -0,0 +1,53 @@
+//
+// Challenge:
+//
+//   You are given a positive number $N.
+//
+//   Write a script to count the total numbrer of set bits of the binary
+//   representations of all numbers from 1 to $N and return
+//   $total_count_set_bit % 1000000007.
+//
+// https://perlweeklychallenge.org/blog/perl-weekly-challenge-079/
+//
+
+//
+// This is A000778 (https://oeis.org/A000788). There's a recursive formala
+// for the number of bits in the binary representation of 0 .. $N:
+//
+//    bits (0)         = 0
+//    bits (2 * N)     =     bits (N) + bits (N - 1) + N
+//    bits (2 * N + 1) = 2 * bits (N)                + N + 1
+//
+
+//
+// Create an interface to read from STDIN
+//
+const rl = require ('readline') . createInterface ({
+    input:  process . stdin,
+});
+
+//
+// Read lines of input, calculate the result, and print it.
+//
+rl . on ('line', (line) => {
+    console . log (bits (+line));  // Unary + numifies
+});
+
+
+//
+// Recursive function to calculate the results (see above).
+// 
+let cache = [];
+function bits (n) {
+    if (n == 0) {
+        return 0;
+    }
+
+    if (!cache [n]) {
+        let half = Math . floor (n / 2);
+        cache [n] = bits (half) + half + 
+                      (n % 2 ? bits (half) + 1 : bits (half - 1));
+    }
+    return cache [n];
+}
+
diff --git a/challenge-079/abigail/node/ch-2.js b/challenge-079/abigail/node/ch-2.js
new file mode 100644
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+++ b/challenge-079/abigail/node/ch-2.js
@@ -0,0 +1,77 @@
+//
+// Challenge:
+//
+//    You are given an array of positive numbers @N.
+//    Write a script to represent it as Histogram Chart and find out
+//    how much water it can trap.
+//
+
+//
+// Create an interface to read from STDIN
+//
+const rl = require ('readline') . createInterface ({
+    input:  process . stdin,
+});
+
+//
+// Read lines of input, calculate the result, and print it.
+//
+rl . on ('line', (line) => {
+    print_histogram (line);
+});
+
+
+//
+// Node doesn't have (s)printf, so we're writing our own formatting function.
+//
+function ff (n, width, pad = " ") {
+    let s = n . toString ();
+    while (s . length < width) {
+        s = pad + s;
+    }
+    return s;
+}
+
+function print_histogram (input) {
+    //
+    // Extract N from the input, find the maximum,
+    // and the width of this maximum.
+    //
+    let N   = input . split (" ") . map (Number);
+    let max = Math  . max (... N);
+    let w   = max   . toString () . length;
+
+    //
+    // Count down volumes from the maximum, down to 1.
+    // For each volume, print the volume, and for each entry
+    // in N, print "#" if the volume is equal or less than
+    // the entry in N, else, print " ". 
+    //
+    for (let volume = max; volume; volume --) {
+        let line = ff (volume, w);
+        for (let i = 0; i < N . length; i ++) {
+            line += " " + ff (volume <= N [i] ? "#" : " ", w);
+        }
+        console . log (line);
+    }
+
+    //
+    // Print the bars
+    //
+    let line = "";
+    line += ff ("_", w, "_");
+    for (let i = 0; i < N . length; i ++) {
+        line += " " + ff ("_", w, "_");
+    }
+    console . log (line);
+
+    //
+    // Finally, print the totals
+    //
+    line = "";
+    line += ff (" ", w);
+    for (let i = 0; i < N . length; i ++) {
+        line += " " + ff (N [i], w);
+    }
+    console . log (line);
+}