替换空格 牛客 java java空格替换字符串

import java.util.Arrays;

public class ReplaceBlank {
    //替换空格，假设原始字符数组空间足够

    public static void replaceBlank(char[] string, int length){
        if (string == null || length <= 0)
            return;

        int originalCount = 0;
        int blankCount = 0;
        int newCount = 0;

        //计数
        int i =0;
        while (string[i] != '\0'){
                originalCount++;
                if (string[i] == ' ')
                    blankCount++;
                i++;
        }
        newCount = originalCount + blankCount * 2;

        //检查内存是否足够
        if (newCount > length)
            return;

        //替换
        int indexOfOriginal = originalCount;
        int indexOfNew = newCount;
        while(indexOfOriginal >= 0 && indexOfNew > indexOfOriginal){
            if (string[indexOfOriginal] != ' ')
                string[indexOfNew--] = string[indexOfOriginal];
            else{
                string[indexOfNew--] = '0';
                string[indexOfNew--] = '2';
                string[indexOfNew--] = '%';
            }
            indexOfOriginal--;
        }
    }

    //测试用例
    public static void main(String[] args){
        String str = "my name is zjp";
        char[] string = Arrays.copyOf(str.toCharArray(), 100);
        ReplaceBlank.replaceBlank(string, 100);

        StringBuilder stringBuilder = new StringBuilder();
        for (char c : string)
            stringBuilder.append(c);
        System.out.println(stringBuilder.toString());
    }

}