这杯咖啡有毒( ? ) -- Reverse a String

た入场券 2022-06-02 04:54 151阅读 0赞

import java.util.Stack;
    
    public class ReverseString { 
    
        public static void main(String[] args) {
            String str = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
            System.out.println(reverse1(str));
            System.out.println(reverse2(str));
            System.out.println(reverse3(str));
            System.out.println(reverse4(str));
            System.out.println(reverse5(str));
            System.out.println(reverse6(str));
            System.out.println(reverse7(str));
            System.out.println(reverse8(str));
            System.out.println(reverse9(str));
        }
    
    
        private static String reverse1(String str) {
            char[] chars = str.toCharArray();
            char temp;
            for (int i = 0, j = chars.length - 1; i <= j; i++, j--) {
                temp = chars[i];
                chars[i] = chars[j];
                chars[j] = temp;
            }
            return new String(chars);
        }
    
        private static String reverse2(String str) {
            char[] chars = str.toCharArray();
            StringBuffer stringBuffer = new StringBuffer();
            for (int i = chars.length - 1; i >= 0; i--) {
                stringBuffer.append(chars[i]);
            }
            return new String(stringBuffer);
        }
    
        private static String reverse3(String str) {
            StringBuffer stringBuffer = new StringBuffer(str);
            stringBuffer.reverse();
            //return new String(stringBuffer);
            return stringBuffer.toString();
        }
    
        private static String reverse4(String str) {
            char[] chars = str.toCharArray();
            String reversedStr = "";
            for (int i = chars.length - 1; i >= 0; i--) {
                reversedStr += chars[i];
            }
            return reversedStr;
        }
    
        private static String reverse5(String str) {
            String reversedStr = "";
            int length = str.length();
            for (int i = 0; i < length; i++) {
                reversedStr = str.charAt(i) + reversedStr;
            }
            return reversedStr;
        }
    
        private static String reverse6(String str) {
            char[] chars = str.toCharArray();
            int n = chars.length - 1;
            int halfLength = n / 2;
            char temp;
            for (int i = 0; i <= halfLength; i++) {
                temp = chars[i];
                chars[i] = chars[n - i];
                chars[n - i] = temp;
            }
            return new String(chars);
        }
    
        private static String reverse7(String str) {
            int length = str.length();
            if (length <= 1) {
                return str;
            }
            String left = str.substring(0, length / 2);
            String right = str.substring(length / 2, length);
            return reverse1(right) + reverse1(left);
        }
    
        private static String reverse8(String str) {
            char[] chars = str.toCharArray();
            int begin = 0;
            int end = str.length() - 1;
            while (begin < end) {
                chars[begin] = (char) (chars[begin] ^ chars[end]);
                chars[end] = (char) (chars[begin] ^ chars[end]);
                chars[begin] = (char) (chars[end] ^ chars[begin]);
                begin++;
                end--;
            }
            return new String(chars);
        }
    
        public static String reverse9(String str) {
            char[] chars = str.toCharArray();
            int length = chars.length;
            Stack<Character> stack = new Stack<>();
            for (int i = 0; i < length; i++) {
                stack.push(chars[i]);
            }
            String reversedStr = "";
            for (int i = 0; i < length; i++)
                reversedStr += stack.pop();
            return reversedStr;
        }
    }