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Balanced parentheses problem added #167
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,28 @@ | ||
| const { balancedParantheses } = require('.'); | ||
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| describe('Balanced parantheses in string', () => { | ||
| let str1, str2, str3, str4; | ||
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| beforeEach(() => { | ||
| str1 = '(())'; | ||
| str2 = '((('; | ||
| str3 = ')('; | ||
| str4 = '((()'; | ||
| }); | ||
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| it('Should return TRUE for `(())`', () => { | ||
| expect(balancedParantheses(str1)).toBe(true); | ||
| }); | ||
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| it('Should return FALSE for `(((`', () => { | ||
| expect(balancedParantheses(str2)).toBe(false); | ||
| }); | ||
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| it('Should return TRUE for `)(`', () => { | ||
| expect(balancedParantheses(str3)).toBe(false); | ||
| }); | ||
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| it('Should return TRUE for `((()`', () => { | ||
| expect(balancedParantheses(str4)).toBe(false); | ||
| }); | ||
| }); |
| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,27 @@ | ||
| /* | ||
| Given a string containing characters and "(" , ")" determine if input string is valid if: | ||
| - Open parantheses is closed by same number & type of parantheses. | ||
| Note that an empty string is also considered valid and any alphanumeric char can be inserted in between pratheses. | ||
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| Example : | ||
| ((())) is balanced. | ||
| ((() is not balanced. | ||
| )( is not balanced. | ||
| We will solve this problem using ES6 - Array Method reduce(). | ||
| */ | ||
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| function balancedParantheses(string) { | ||
| return !string.split('').reduce(function(prev, char) { | ||
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There was a problem hiding this comment. Choose a reason for hiding this commentThe reason will be displayed to describe this comment to others. Learn more. How about an arrow function here? |
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| if (prev < 0) return prev; | ||
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| if (char === '(') return ++prev; | ||
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| if (char === ')') return --prev; | ||
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| return prev; | ||
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Comment on lines
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There was a problem hiding this comment. Choose a reason for hiding this commentThe reason will be displayed to describe this comment to others. Learn more. Can we use a switch case here? There was a problem hiding this comment. Choose a reason for hiding this commentThe reason will be displayed to describe this comment to others. Learn more. I think switch case isn't needed here since we have to check two variables char & prev here. can i use ternary operator instead ? There was a problem hiding this comment. Choose a reason for hiding this commentThe reason will be displayed to describe this comment to others. Learn more. Something like this return !string.split('').reduce((prev, char) => { const result = prev < 0 ? prev : char === '(' ? ++prev : char === ')' ? --prev : prev; return result; }, 0); There was a problem hiding this comment. Choose a reason for hiding this commentThe reason will be displayed to describe this comment to others. Learn more. The above snippet is not readable enough There was a problem hiding this comment. Choose a reason for hiding this commentThe reason will be displayed to describe this comment to others. Learn more. so, if else pattern will be fine right ? switch case will add more code since we have to check cases for prev & char. |
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| }, 0); | ||
| } | ||
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| module.exports = { | ||
| balancedParantheses, | ||
| }; | ||