Javascript solution for Week 079, part 2.

1 files changed, 77 insertions, 0 deletions

diff --git a/challenge-079/abigail/node/ch-2.js b/challenge-079/abigail/node/ch-2.js
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+//
+// 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);
+}