leetcode 844.比较含退格的字符串

class Solution {
public:
    bool backspaceCompare(string s, string t) {
        int lens=s.size();
        int lent=t.size();
        int slow=0;
        int clear=0;
        int fast=0;
        while(s[clear]=='#'){
            
            fast++;
            clear++;
        }

        for(;fast<lens;fast++){
            if(s[fast]!='#'){
                s[slow]=s[fast];
                slow++;
            }else{
                if(slow>0) slow--;
            }
        }
        
        s=s.substr(0,slow);

        slow=0;
        clear=0;
        fast=0;
        while(t[clear]=='#'){
            
            fast++;
            clear++;
        }
        for(;fast<lent;fast++){
            if(t[fast]!='#'){
                t[slow]=t[fast];
                slow++;
            }else{
                if(slow>0) slow--;
            }
        }
        
        t=t.substr(0,slow);

        if(s==t){
            return true;
        }
        return false;
        

        }
    
};

注意退格次数不越界