Java程序猿笔试面试之String1

Posted 2020-06-09

1.怎样实现字符串的反转比如：“how are you”--->“you are how”

public class InverseString {
    public  void swap(char[] arr,int front,int end){//将char[]反转
    	 while(front<end){
    		char temp=arr[end];
    		 arr[end]=arr[front];
    		 arr[front]=temp;
    		 front++;
    		 end--;
    	 }
    }
    public String swapWords(String s){
    	char[] arr=s.toCharArray();//将字符串转化为char类型数组
    	swap(arr, 0, arr.length-1);//先将char[]反转
    	int begin=0;
    	for(int i=1;i<arr.length;i++){//仅仅要遇到空格就将空格之前的单词反转
    		if("".equals(arr[i])){
    			swap(arr, begin, i-1);
    			begin=i+1;
    		}
    	}
    	swap(arr, begin, arr.length-1);//由于最后一位没有空格所以最后一个单词手动反转
    	return new String(arr);
    }
    
   
	public static void main( String[] args){
    	String s="how are you";
    	System.out.println(new InverseString().swapWords(s));
    	
    	
    }
}