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fix(curriculum) more comprehensive test for 24 game (#47229)
* fix - more comprehensive test for 24 game * fix precidence comparison * error on bad characters * well that's embarassing
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Jeremy L Thompson
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@@ -39,28 +39,28 @@ Implement a function that takes a string of four digits as its argument, with ea
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assert(typeof solve24 === 'function');
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```
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`solve24("4878")` should return `(7-8/8)*4` or `4*(7-8/8)`
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`solve24("4878")` should return `(7-8/8)*4`, `4*(7-8/8)`, or a similar valid string
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```js
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assert(include(answers[0], removeParentheses(solve24(testCases[0]))));
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assert(isValidSolution_(solve24(testCases_[0])));
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```
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`solve24("1234")` should return any arrangement of `1*2*3*4`
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`solve24("1234")` should return `1*2*3*4` or a similar valid string
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```js
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assert(include(answers[1], removeParentheses(solve24(testCases[1]))));
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assert(isValidSolution_(solve24(testCases_[1])));
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```
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`solve24("6789")` should return `(6*8)/(9-7)` or `(8*6)/(9-7)`
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`solve24("6789")` should return `(6*8)/(9-7)`. `(8*6)/(9-7)`, or a similar valid string
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```js
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assert(include(answers[2], removeParentheses(solve24(testCases[2]))));
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assert(isValidSolution_(solve24(testCases_[2])));
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```
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`solve24("1127")` should return a permutation of `(1+7)*(1+2)`
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`solve24("1127")` should return `(1+7)*(1+2)` or a similar valid string
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```js
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assert(include(answers[3], removeParentheses(solve24(testCases[3]))));
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assert(isValidSolution_(solve24(testCases_[3])));
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```
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# --seed--
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@@ -68,56 +68,101 @@ assert(include(answers[3], removeParentheses(solve24(testCases[3]))));
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## --after-user-code--
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```js
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const testCases = [
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const testCases_ = [
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'4878',
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'1234',
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'6789',
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'1127'
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];
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const answers = [
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['(7-8/8)*4', '4*(7-8/8)', '(4-8+7)*8', '(4+7-8)*8', '(7+4-8)*8', '(7-8+4)*8', '8*(4-8+7)', '8*(4+7-8)', '8*(7+4-8)', '8*(7-8+4)'],
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['1*2*3*4', '1*2*4*3', '1*3*2*4', '1*3*4*2', '1*4*2*3', '1*4*3*2', '2*1*3*4', '2*1*4*3', '2*3*1*4', '2*3*4*1', '2*4*3*1', '2*4*1*3', '3*1*2*4', '3*1*4*2', '3*2*1*4', '3*2*4*1', '3*4*1*2', '3*4*2*1', '4*1*2*3', '4*1*3*2', '4*2*1*3', '4*2*3*1', '4*3*1*2', '4*3*2*1', '(1+2+3)*4', '(1+3+2)*4', '(2+1+3)*4', '(2+3+1)*4', '(3+1+2)*4', '(3+2+1)*4', '4*(1+2+3)', '4*(2+1+3)', '4*(2+3+1)', '4*(3+1+2)', '4*(3+2+1)'],
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['(6*8)/(9-7)', '(8*6)/(9-7)', '6*8/(9-7)', '8*6/(9-7)'],
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['(1+7)*(2+1)', '(1+7)*(1+2)', '(1+2)*(1+7)', '(1+2)*(7+1)', '(2+1)*(1+7)', '(7+1)*(2+1)']
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];
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function include(ansArr, res) {
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const index = ansArr.indexOf(res);
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return index >= 0;
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const OPERATORS_ = {
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"+": (a, b) => a + b,
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"-": (a, b) => a - b,
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"*": (a, b) => a * b,
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"/": (a, b) => a / b,
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}
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//The main method for detecting single parentheses
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function removeParentheses(ans) {
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for (let i = 0; i < ans.length; i++) {
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if (!isNaN(ans[i])) {
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ans = removeParenthesesHelper(ans, i);
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const PRECIDENCE_ = {
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"+": 1,
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"-": 1,
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"*": 2,
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"/": 2,
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}
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function evaluate_(expression) {
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expression = expression.replace('/\s+/g', '');
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const stack = [];
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let postfix = "";
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// Convert from infix to postfix
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let head = 0;
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while (head < expression.length) {
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let c = expression[head];
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switch (c) {
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case "(":
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stack.push(c);
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break;
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case ")":
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let last = stack.pop();
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while (last !== "(") {
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postfix += last;
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last = stack.pop();
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}
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break;
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case "+":
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case "-":
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case "*":
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case "/":
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while (stack.length &&
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PRECIDENCE_[c] <= PRECIDENCE_[stack[stack.length-1]]) {
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postfix += stack.pop();
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}
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stack.push(c);
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break;
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case "0":
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case "1":
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case "2":
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case "3":
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case "4":
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case "5":
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case "6":
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case "7":
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case "8":
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case "9":
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postfix += c;
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break;
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default:
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return false;
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}
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head++;
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}
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// Clear out stack
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while (stack.length) {
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postfix += stack.pop();
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}
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// Evaluate postfix
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for (let c of postfix) {
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switch (c) {
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case "+":
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case "-":
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case "*":
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case "/":
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const b = +stack.pop();
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const a = +stack.pop();
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stack.push(OPERATORS_[c](a, b));
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break;
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default:
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stack.push(c);
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}
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}
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return ans;
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return stack.pop();
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}
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//Helper to remove left and right parantheses
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function removeParenthesesHelper(ans, i) {
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while (i > 0 && i < ans.length - 1) {
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if (ans[i - 1] === '(' && ans[i + 1] === ')') {
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//Paranthesis detected. Remove them.
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ans = replaceChar(ans, '', i - 1);
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ans = replaceChar(ans, '', i);
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i--;
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} else {
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return ans;
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}
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}
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return ans;
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}
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//Replace a character at a given index for the provided character
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function replaceChar(origString, replaceChar, index) {
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let firstPart = origString.substr(0, index);
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let lastPart = origString.substr(index + 1);
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let newString = firstPart + replaceChar + lastPart;
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return newString;
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// Check solution validity
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function isValidSolution_(userSolution) {
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return evaluate_(userSolution) === 24;
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}
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```
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