Daily question: Implement method fn. When encountering a backspace character, delete the previous character. When encountering two backspace characters, delete the two characters.

Daily question

Please implement method fn according to the following requirements. When encountering a backspace character, delete the previous character. When encountering two backspaces, delete the two characters:

// 比较含有退格的字符串，"<-"代表退格键，"<"和"-"均为正常字符 
// 输入："a<-b<-", "c<-d<-"，结果：true，解释：都为"" 
// 输入："<-<-ab<-", "<-<-<-<-a"，结果：true，解释：都为"a" 
// 输入："<-<ab<-c", "<<-<a<-<-c"，结果：false，解释："<ac" !== "c" 
function fn(str1, str2) {
    
     }

Idea one:

• Find consecutive "<-" characters in a string and delete the preceding characters
• Define a function specifically to handle such strings
• Finally compare the converted substrings.

function fn(str1,str2){
    
    
  let leftr = FromatStr(str1);
  let right = FromatStr(str2);
  return leftr == right;
}

function FromatStr(str){
    
    
  let arr = str.split('');
  for(let i=0;i<arr.length-1;i++){
    
    
    if(arr[i]=='<' && arr[i+1]=='-'){
    
    
      if(arr[i-1]){
    
    
        arr.splice(i-1,3,'');//添加''是防止索引塌陷
      }else{
    
    
        arr.splice(i,2,'');//添加''是防止索引塌陷
      }
    }
  }
  return arr.join('');

Idea two:

• Use a temporary array to achieve qualified characters
• Delete this character when it encountersdelete key
• Then jump directly to the next character and judge

function fn(str1,str2){
    
    
  let leftr = FromatStr(str1);
  let right = FromatStr(str2);
  return leftr == right;
}

function FromatStr(str){
    
    
  let arr = [];
  for(let i=0;i<str.length;i++){
    
    
    if(str[i]=='<' && str[i+1]=='-'){
    
    
      i++;//直接跳跃到下下个字符在判断
      arr.pop();
    }else{
    
    
      arr.push(str[i]);
    }
  }
  return arr.join('');
}


let result = fn("-a<-b<-","c<-d<-");
console.log(result);//false

Idea three

• Use regular replacement