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LeetCode : 344. Reverse String

2020-11-11
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(Easy) Reverse String

Problem

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"]

Code (20. 11. 11)

public void reverseString(char[] s) {
    int length = s.length;
    char[] ans = new char[length];

    for (int i = 0; i < length; i++) {
        ans[i] = s[length - 1 - i];
    }

    for (int i = 0; i < length; i++) {
        s[i] = ans[i];
    }
}
  • 막 풀어도 될까 했는데 풀리는구나.

    그래도 좋은 코드 참고하자.


Feed Back

Case 1

public void reverseString(char[] s) {
    int lo = 0;
    int hi = s.length -1;
    
    while(lo<hi) {
        char temp = s[lo];
        s[lo] = s[hi];
        s[hi] = temp;
        lo++;
        hi--;
    }
}

Reference


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