面试题 01.06. 字符串压缩

class Solution {
public:
    string compressString(string S) {
        string s1="";
        int n=S.size();
        s1.insert(s1.begin(),S[0]);
        int a=1;
        for(int i=1;i<n;i++){
            if(S[i]==S[i-1]){
                a+=1;
            }
            else{
                // cout<<char(a)<<endl;
                if(a<=9)
                    s1.push_back(a+48);
                else {//当a>9例如a=100，转化为001分别取出每一位数并输入字符串
                    int temp=a;
                    int sum=0;
                    int j=0;
                    while(temp){
                        j+=1;
                        int num=temp%10;
                        
                        sum=num+10*sum;
                        temp=temp/10;
                    }
                    int t=sum;
                    int k=0;
                     while(t){k++;
                        int n=t%10;
                        s1.push_back(n+48);
                        t=t/10;
                    }
                    while(j!=k){
                        k++;
                        s1.push_back(48);
                    }
                    
                }
                s1.push_back(S[i]);
                a=1;
            }
            if(i==n-1){
                          int temp=a;
                    int sum=0;
                    int j=0;
                    while(temp){
                        j+=1;
                        int num=temp%10;
                        
                        sum=num+10*sum;
                        temp=temp/10;
                    }
                    int t=sum;
                    int k=0;
                     while(t){k++;
                        int n=t%10;
                        s1.push_back(n+48);
                        t=t/10;
                    }
                    while(j!=k){
                        k++;
                        s1.push_back(48);
                    }
            }
          
        }
        return s1.size()<n?s1:S;
    }
};

class Solution:
    def compressString(self, S: str) -> str:
        i=0
        res=''
        while i<len(S):
            j=i
            while j<len(S)and S[j]==S[i]:
                j+=1
            res+=S[i]+str(j-i)
            i=j;
        return res if len(res)<len(S) else S