344. Reverse String

Difficulty: Easy
478 / 478 test cases passed.
Runtime: 204 ms
Memory Usage: 18 MB

Author: YuriSpiridonov

Easy/344.ReverseString.py

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+"""
+    Write a function that reverses a string. The input string is given as an 
+    array of characters char[].
+    Do not allocate extra space for another array, you must do this by 
+    modifying the input array in-place with O(1) extra memory.
+    You may assume all the characters consist of printable ascii characters.
+    
+    Example:
+    Input: ["h","e","l","l","o"]
+    Output: ["o","l","l","e","h"]
+"""
+#Difficulty: Easy
+#478 / 478 test cases passed.
+#Runtime: 204 ms
+#Memory Usage: 18 MB
+
+#Runtime: 204 ms, faster than 91.57% of Python3 online submissions for Reverse String.
+#Memory Usage: 18 MB, less than 5.81% of Python3 online submissions for Reverse String.
+
+class Solution:
+    def reverseString(self, s: List[str]) -> None:
+        i = 0
+        l = len(s) - 1
+        while i <= l:
+            s[i], s[l] = s[l], s[i]
+            i += 1
+            l -= 1
+        return s