557 solved. (#63)

Author: zwfang

README.md

@@ -54,6 +54,7 @@ continually updating 😃.
 * [344. Reverse String](./src/0344_reverse_string/reverse_string.go)   *`string;`*  *`double index`*
 * [345. Reverse Vowels of a String](./src/0345_reverse_vowels_of_a_string/reverse_vowels.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`*
+* [557. Reverse Words in a String III](src/0557_reverse_words_in_a_string_3/reverse_words_in_a_string_3.go)
 
 ### Linked List
 * [2. Add Two Numbers](./src/0002_add_two_numbers/add_two_numbers.go)   *`recursion;`*  *`math`*

src/0557_reverse_words_in_a_string_3/reverse_words_in_a_string_3.go

@@ -0,0 +1,36 @@
+/*
+557. Reverse Words in a String III
+https://leetcode.com/problems/reverse-words-in-a-string-iii/
+
+Given a string, you need to reverse the order of characters in each word within a sentence
+while still preserving whitespace and initial word order.
+
+Note: In the string, each word is separated by single space and there will not be any extra space in the string.
+*/
+// time: 2019-01-08
+
+package rwias3
+
+import "strings"
+
+// split and reverse
+// time complexity: O(len(s))
+// space complexity: O(n)
+func reverseWords(s string) string {
+	words := strings.Split(s, " ")
+
+	var temp []string
+	for _, word := range words {
+		temp = append(temp, reverseString(word))
+	}
+	return strings.Join(temp, " ")
+}
+
+func reverseString(s string) string {
+	runes := []rune(s)
+
+	for start, end := 0, len(runes)-1; start < end; start, end = start+1, end-1 {
+		runes[start], runes[end] = runes[end], runes[start]
+	}
+	return string(runes)
+}

src/0557_reverse_words_in_a_string_3/reverse_words_in_a_string_3_test.go

@@ -0,0 +1,12 @@
+package rwias3
+
+import "testing"
+
+func TestReverseWords(t *testing.T) {
+	s := "Let's take LeetCode contest"
+	expected := "s'teL ekat edoCteeL tsetnoc"
+
+	if res := reverseWords(s); res != expected {
+		t.Errorf("expected %s, got %s", expected, res)
+	}
+}

src/README.md

@@ -94,6 +94,7 @@
 |0447|[Number of Boomerangs](./0447_number_of_boomerangs/number_of_boomerangs.go)|Easy||
 |0454|[4Sum II](./0454_4sum2/4sum2.go)|Medium||
 |0455|[Assign Cookies](./0455_assign_cookies/assign_cookies.go)|Easy|*`greedy algorithm`*|
+|0557|[557. Reverse Words in a String III](0557_reverse_words_in_a_string_3/reverse_words_in_a_string_3.go)|Easy|*`string`*|
 |0674|[674. Longest Continuous Increasing Subsequence](0674_longest_continuous_increasing_subsequence/lcis.go)|Easy||
 |0704|[Binary Search](0704_binary_search/binary_search.go)|Easy|*`binary search`*|
 |0713|[713. Subarray Product Less Than K](0713_subarray_product_less_than_k/spltk.go)|Medium|*`sliding window`*|