遍历字符串中的字符并删除连续的重复项 [英] Iterate through characters in a string and remove consecutive duplicates

问题描述

我正在尝试遍历字符串并删除连续的重复字母.

I am trying to iterate through a string and remove consecutive duplicates letter.

ABBACBAABCB-->AACBAABCB-->CBAABCB-->CBBCB-->CCB-->B

我的想法是遍历字符串并删除 do-while 循环内的重复项.

My Idea was to iterate through the string and remove duplicates inside a do-while loop.

我的代码:

class Main {
    public static String list = "ABBACBAABCB";
    public static boolean notvalid = true;

    public static void main(String[] args) {
        do {
            String r = Itterate(list);
            isvalid(r);
            //list = r does not work
        } while (notvalid);

    }

    public static String Itterate(String str) {
        for (int i = 1; i < list.length(); i = i + 1) {
            char Curr = list.charAt(i);
            char Prev = list.charAt(i - 1);
            if (Curr == Prev) {
                String results = str.substring(0, i - 1)
                        + str.substring(i, str.length());
                return results;
            }
        }
        return str;
    }

    public static void isvalid(String str) {
        for (int i = 1; i < str.length(); i = i + 1) {
            char curr = str.charAt(i);
            char prev = str.charAt(i - 1);
            if (curr == prev) {
                notvalid = true;
                return;
            }
        }
        notvalid = false;
        return;
    }
}

显然这是行不通的，它只会永远循环下去.

Obviously this doesn't work, it simply loop forever.

根据我的收集，由于字符串是不可变的，因此无法在Java上执行 list = results .

From what I have gathered you can't do list = results on java as string are immutable.

如何使用Java做到这一点?

How can this be done with Java?

推荐答案

您应该使用这样的堆栈.

You should use a stack like this.

static String removeConsecutiveDupplicatesLetter(String s) {
    Stack<Character> stack = new Stack<>();
    for (char c : s.toCharArray())
        if (!stack.isEmpty() && stack.peek() == c)
            stack.pop();
        else
            stack.push(c);
    return stack.stream().map(String::valueOf).collect(Collectors.joining());
}

还有

String s = "ABBACBAABCB";
System.out.println(removeConsecutiveDupplicatesLetter(s));

结果:

B

这是这样的.

stack    c
-------  -
[]       A 
[A]      B
[A B]    B
[A]      A
[]       C
[C]      B
[C B]    A
[C B A]  A
[C B]    B
[C]      C
[]       B
[B]

您也可以将 char [] 用作堆栈，而不是 Stack .

You can also use char[] as a stack instead of Stack.

static String removeConsecutiveDupplicatesLetter(String s) {
    int length = s.length();
    char[] stack = new char[length];
    int index = 0;
    for (char c : s.toCharArray())
        if (index > 0 && stack[index - 1] == c)
            --index;
        else
            stack[index++] = c;
    return new String(stack, 0, index);
}

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