将一个字符串，按字符串的顺序，将字符改成大写，并保存到数组中。

本文介绍了一种将字符串转换为墨西哥波浪形式的方法，通过创建一个函数，将输入的字符串中每个字符依次转换为大写，形成类似墨西哥波浪的效果。文章提供了两种实现方式，并附带了代码示例。

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In this simple Kata your task is to create a function that turns a string into a Mexican Wave. You will be passed a string and you must return that string in an array where an uppercase letter is a person standing up.

1. The input string will always be lower case but maybe empty.

2. If the character in the string is whitespace then pass over it as if it was an empty seat.

wave("hello") => ["Hello", "hEllo", "heLlo", "helLo", "hellO"]

代码：

注意：方法二有问题

import org.springframework.util.StringUtils;

import java.util.ArrayList;
import java.util.List;

/**
 * @description:
 * @create: 2019/04/15 13:46
 */
public class MexicanWave {

    //方法一
    public static String[] wave(String str) {
        List<String> list = new ArrayList<>();
        for (int i = 0; i < str.length(); i++) {
            char ch = str.charAt(i);
            if (ch == ' ') continue;
            list.add(str.substring(0,i) + Character.toUpperCase(ch) + str.substring(i+1));
        }
        return list.toArray(new String[0]);
    }

    //方法二
    public static String[] wave1(String str) {
        if(StringUtils.isEmpty(str)){
           return new String[]{};
        }
        String start=String.valueOf(str.charAt(0));
        String end=String.valueOf(str.charAt(str.length()-1));
        int startIn=0;
        int endIn=0;
        if(start.equals(" ")){
            startIn=1;
        }
        if(end.equals(" ")){
            endIn=1;
        }
        int a=0;
        if(str.contains(" ")){
            a=str.indexOf(" ");
            str=str.replaceAll(" ","");
        }
        String[] arr=new String[str.length()];
        for (int i=0;i<str.length();i++){
            String s=String.valueOf(str.charAt(i)).trim().toUpperCase();
            if(!StringUtils.isEmpty(s)){
                String newStr;
                if(i==0){
                    newStr=s+str.substring(1);
                }else if(i>0&&i<str.length()-1){
                    newStr=str.substring(0,i)+s+str.substring(i+1);
                }else {
                    newStr=str.substring(0,i)+s;
                }
                if(a>0){
                    newStr=newStr.substring(0,a)+" "+newStr.substring(a);
                }
                if(startIn>0){
                    newStr=" "+newStr;
                }
                if(endIn>0){
                    newStr=newStr+" ";
                }
                arr[i]=newStr;
            }
        }
        return arr;
    }


    public static void main(String[] args) {
//        System.out.println(Arrays.toString(wave("hello")));
//        System.out.println(Arrays.toString(wave("two words")));
//        System.out.println(Arrays.toString(wave(" gap ")));
//        System.out.println(Arrays.toString(wave("")));
    }
}