344. Reverse String

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題目敘述

Write a function that reverses a string. The input string is given as an array of characters s.

You must do this by modifying the input array in-place with O(1) extra memory.

Example 1

Input: s = [“h”,“e”,“l”,“l”,“o”] Output: [“o”,“l”,“l”,“e”,“h”]

Example 2

Input: s = [“H”,“a”,“n”,“n”,“a”,“h”] Output: [“h”,“a”,“n”,“n”,“a”,“H”]

解題思路

Solution

class Solution {
    public void reverseString(char[] s) {
        int i = 0, j = s.length - 1;
        
        while(i < j) {
            char temp = s[i];
            s[i++] = s[j];
            s[j--] = temp;
        }
    }
}