52 lines
1.6 KiB
JavaScript
52 lines
1.6 KiB
JavaScript
function twentyfour(numbers, input) {
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var invalidChars = /[^\d\+\*\/\s-\(\)]/;
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var validNums = function(str) {
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// Create a duplicate of our input numbers, so that
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// both lists will be sorted.
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var mnums = numbers.slice();
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mnums.sort();
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// Sort after mapping to numbers, to make comparisons valid.
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return str.replace(/[^\d\s]/g, " ")
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.trim()
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.split(/\s+/)
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.map(function(n) { return parseInt(n, 10); })
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.sort()
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.every(function(v, i) { return v === mnums[i]; });
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};
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var validEval = function(input) {
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try {
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return eval(input);
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} catch (e) {
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return {error: e.toString()};
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}
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};
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if (input.trim() === "") return "You must enter a value.";
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if (input.match(invalidChars)) return "Invalid chars used, try again. Use only:\n + - * / ( )";
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if (!validNums(input)) return "Wrong numbers used, try again.";
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var calc = validEval(input);
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if (typeof calc !== 'number') return "That is not a valid input; please try again.";
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if (calc !== 24) return "Wrong answer: " + String(calc) + "; please try again.";
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return input + " == 24. Congratulations!";
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};
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// I/O below.
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while (true) {
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var numbers = [1, 2, 3, 4].map(function() {
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return Math.floor(Math.random() * 8 + 1);
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});
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var input = prompt(
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"Your numbers are:\n" + numbers.join(" ") +
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"\nEnter expression. (use only + - * / and parens).\n", +"'x' to exit.", "");
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if (input === 'x') {
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break;
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}
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alert(twentyfour(numbers, input));
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}
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