Create palindrome.dart #187
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please add the label 'hacktoberfest-accepted' when accepting the pr request |
strings/palindrome.dart
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| print('Enter Words or number'); | ||
| // User enter a string or a number | ||
| String? original = 'hannah'; | ||
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| // then we will reverse the input | ||
| String? reverse = original.split('').reversed.join(''); | ||
| // then we will compare | ||
| if(original == reverse) | ||
| { | ||
| print('Its A Palindrome'); | ||
| }else{ | ||
| print('Its A Not Palindrome'); | ||
| } |
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Can we optimise this? can we have an algorithm with lesser space complexity?
Also reduce the use of inbuilt functions like reversed. split and join. The Algorithm will be quite inefficient.
strings/palindrome.dart
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| print('Enter Words or number'); | ||
| // User enter a string or a number | ||
| String? original = 'hannah'; | ||
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| // then we will reverse the input | ||
| String? reverse = original.split('').reversed.join(''); | ||
| // then we will compare | ||
| if(original == reverse) | ||
| { | ||
| print('Its A Palindrome'); |
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I am very new to this. What are tests? I will be updating everything as you requested
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You can check out other files. to see how tests are implemented.
You can also read up from the official docs:
https://pub.dev/packages/test
strings/palindrome.dart
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| void main(){ | |||
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create a function outside main which checks for palindrome.
strings/palindrome.dart
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| String? original = 'hannah'; | ||
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| // then we will reverse the input | ||
| String? reverse = original.split('').reversed.join(''); |
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I have added the tests and other requirements. Do I need to do another pull request or you can see the changes? Sorry for asking dumb questions |
| if (original == reverseUsingLoop) { | ||
| // print('Its A Palindrome'); | ||
| } else { | ||
| // print('Its A Not Palindrome'); | ||
| } | ||
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| if (original == reverseUsingSplit) { | ||
| // print('Its A Palindrome'); | ||
| } else { | ||
| // print('Its A Not Palindrome'); | ||
| } | ||
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| if (original == reverseUsingRunes) { | ||
| // print('Its A Palindrome'); | ||
| } else { | ||
| // print('Its A Not Palindrome'); | ||
| } | ||
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| if (original == reverseUsingCodeUnits) { | ||
| // print('Its A Palindrome'); | ||
| } else { | ||
| // print('Its A Not Palindrome'); | ||
| } | ||
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What's the use of this code section?
| group('Palindrome Check', () { | ||
| test('Using loop to reverse a string.', () { | ||
| var string = 'hannah'; | ||
| expect(string, equals(reverseStringUsingLoop(string))); | ||
| }); | ||
| test('Using split to reverse a string.', () { | ||
| var string = 'hannah'; | ||
| expect(string, equals(reverseStringUsingSplit(string))); | ||
| }); | ||
| test('Using runes to reverse a string.', () { | ||
| var string = 'hannah'; | ||
| expect(string, equals(reverseStringUsingRunes(string))); | ||
| }); | ||
| test('Using code units to reverse a string.', () { | ||
| var string = 'hannah'; | ||
| expect(string, equals(reverseStringUsingCodeUnits(string))); | ||
| }); | ||
| }); |
| String reverseStringUsingLoop(String input) { | ||
| String reversed = ""; | ||
| for (int index = input.length - 1; index >= 0; index--) { | ||
| reversed += input[index]; | ||
| } | ||
| return reversed; | ||
| } | ||
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| String reverseStringUsingSplit(String input) { | ||
| var chars = input.split(''); | ||
| return chars.reversed.join(); | ||
| } | ||
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| String reverseStringUsingRunes(String input) { | ||
| var chars = input.runes.toList(); | ||
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| return String.fromCharCodes(chars.reversed); | ||
| } | ||
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| String reverseStringUsingCodeUnits(String input) { | ||
| return String.fromCharCodes(input.codeUnits.reversed); | ||
| } |
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All of the reversal logic are running on O(N) space. can we optimise to make it run on O(1) space.
Welcome to Dart community
Describe your change:
Checklist:
Fixes: #{$ISSUE_NO}.