diff --git a/README.md b/README.md index 9e4351b..e831a33 100644 --- a/README.md +++ b/README.md @@ -34,6 +34,7 @@ continually updating πŸ˜ƒ. * [67. Add Binary](./src/0067_add_binary/add_binary.go) *`brute force`* * [76. Minimum Window Substring](./src/0076_minimum_window_substring/minimum_window_substring.go) *`sliding window`* * [125. Valid Palindrome](./src/0125_valid_palindrome/valid_palindrome.go) *`string;`* *`double index`* +* [344. Reverse String](0344_reverse_string/reverse_string.go) *`string;`* *`double index`* * [438. Find All Anagrams in a String](./src/0438_all_anagrams_in_a_string/all_anagrams_in_a_string.go) *`sliding window`* ### Linked List diff --git a/src/0344_reverse_string/reverse_string.go b/src/0344_reverse_string/reverse_string.go new file mode 100644 index 0000000..520cf18 --- /dev/null +++ b/src/0344_reverse_string/reverse_string.go @@ -0,0 +1,41 @@ +/* +344. Reverse String +https://leetcode.com/problems/reverse-string/ + +Write a function that takes a string as input and returns the string reversed. +*/ +// time: 2018εΉ΄12月26ζ—₯ + +package reversestring + +// double index +// time complexity: O(n) +// space complexity: O(1) +func reverseString(s string) string { + var ( + l int + r = len(s) - 1 + ) + + for r>= l { + charL := s[l] + charR := s[r] + s = s[:r] + string(charL) + s[r+1:] + s = s[:l] + string(charR) + s[l+1:] + r-- + l++ + } + return s +} + +// double index +// time complexity: O(n) +// space complexity: O(n) +func reverseString1(s string) string { + sLen := len(s) + runes := []rune(s) + for i := 0; i < sLen/2; i++ { + runes[i], runes[sLen-i-1] = runes[sLen-i-1], runes[i] + } + return string(runes) +} diff --git a/src/0344_reverse_string/reverse_string_test.go b/src/0344_reverse_string/reverse_string_test.go new file mode 100644 index 0000000..784c521 --- /dev/null +++ b/src/0344_reverse_string/reverse_string_test.go @@ -0,0 +1,45 @@ +package reversestring + +import "testing" + +func TestReverseString(t *testing.T) { + testCases := []string{ + "hello", + "A man, a plan, a canal: Panama", + "", + "ab", + } + expected := []string{ + "olleh", + "amanaP :lanac a ,nalp a ,nam A", + "", + "ba", + } + + for index, data := range testCases { + if res := reverseString(data); res != expected[index] { + t.Errorf("expected %s, got %s", expected[index], res) + } + } +} + +func TestReverseString1(t *testing.T) { + testCases := []string{ + "hello", + "A man, a plan, a canal: Panama", + "", + "ab", + } + expected := []string{ + "olleh", + "amanaP :lanac a ,nalp a ,nam A", + "", + "ba", + } + + for index, data := range testCases { + if res := reverseString1(data); res != expected[index] { + t.Errorf("expected %s, got %s", expected[index], res) + } + } +} diff --git a/src/README.md b/src/README.md index 003f284..c1c10f0 100644 --- a/src/README.md +++ b/src/README.md @@ -40,6 +40,7 @@ |0283|[Move Zeroes(solution1)](./0283_move_zeroes/move_zeroes.go)
[Move Zeroes(solution2)](./0283_move_zeroes/move_zeroes2.go)|Easy|*`array`*| |0300|[Longest Increasing Subsequence](./0300_longest_increasing_subsequence/lis.go)|Medium|*`dp`*| |0343|[Integer Break](./0343_integer_break/integer_break.go)|Medium|*`recursion;`* *`memory search;`* *`dynamic programming`*| +|0344|[344. Reverse String](0344_reverse_string/reverse_string.go)|Easy|*`double index`*| |0349|[Intersection of Two Arrays](./0349_intersection_of_2_arrays/intersection_of_two_arrays.go)|Easy|*`set`*| |0350| [Intersection of Two Arrays II](./0350_intersection_of_two_arrays2/intersection_of_two_arrays2.go)|Easy|*`map`*| |0376|[Wiggle Subsequence](./0376_wiggle_subsequence/wiggle_subsequence.go)|Medium|*`dp`*|

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