JavaScript - Advanced Algorithms(Greedy Algorithms, the coin-changing problem)

Data Structures and Algorithms With Javascript
(O'Reilly Media)
Michael McMillan(著)

開発環境

• OS X El Capitan - Apple (OS)
• Emacs (Text Editor)
• JavaScript (プログラミング言語)
• SpiderMonkey, Node.js(V8) (JavaScript engine)

Data Structures and Algorithms With Javascript (Michael McMillan(著)、O'Reilly Media)のChapter 14(Advanced Algorithms)、Exercises 3.(No. 6553)を解いてみる。

Exercises 3.(No. 6553)

JavaScript(Emacs)

/*jslint         browser : true, continue : true,
  devel  : true, indent  : 4,    maxerr   : 50,
  newcap : true, nomen   : true, plusplus : false,
  regexp : true, sloppy  : true, vars     : false,
  white  : true
*/

/*global */
var orig_amt = 0.3,
    coins = [],
    makeChange,
    showChange;

makeChange = function (orig_amt, coins) {
    var remain_amt = 0;

    if (orig_amt % 0.25 < orig_amt) {
        coins[2] = parseInt(orig_amt / 0.25, 10);
        remain_amt = orig_amt % 0.25;
        orig_amt = remain_amt;
    }
    if (orig_amt % 0.05 < orig_amt) {
        coins[1] = parseInt(orig_amt / 0.05, 10);
        remain_amt = orig_amt % 0.05;
        orig_amt = remain_amt;
    }
    coins[0] = parseInt(orig_amt / 0.01, 10);
};

showChange = function (coins) {
    if (coins[2] > 0) {
        console.log('Number of quarters - ' + coins[2] + ' - ' +
                    coins[2] * 0.25);
    }
    if (coins[1] > 0) {
        console.log('Number of nickles - ' + coins[1] + ' - ' +
                    coins[1] * 0.05);
    }
    if (coins[0] > 0) {
        console.log('Number of pennies - ' + coins[0] + ' - ' +
                    coins[0] * 0.01);
    }
};

makeChange(orig_amt, coins);
showChange(coins);

出力結果(Terminal, shell, SpiderMonkey)

$ jslint sample3.js

sample3.js is OK.
$ node sample3.js
Number of quarters - 1 - 0.25
Number of pennies - 4 - 0.04
$